Probes have excellent handling when completely stock. The handling is good enough for the average driver as well as performance enthusiasts, but of course, there are people who desire to go through a curve quicker, or to get off the line faster. Upgrading the tires is a good idea for anyone, but upgrading the suspension should be considered with great care. Handling that's stiffer will increase the harshness of the overall ride, as well as other possible performance problems.

The softer stock suspension will allow the tires to go over a small bump without loosing traction. This keeps the tires in constant contact with the ground keeping a solid grip on the road throughout a sharp corner. If you upgrade the suspension and the stiffer shocks go over the same bump, the tire is more likely to lift from the ground, reducing the contact patch between the tire and the ground, which can cause the tire to loose its grip on the road. You should consider the pros vs the cons on shocks before upgrading anything on your suspension, especially if you area has poor roads.

Key
Pros: The benefits of a particular upgrade.
Cons: The down side of a particular upgrade.
Cost: Approximate price range based on numerous quotes and price sheets.
HP Gains: Estimated increase in horsepower you can expect from a particular upgrade. Not necessarily peak horsepower.
Manufacturers: Examples of particular companies that sell a particular upgrade.
Availability: Which Probes the upgrade is for.

Contents
Adjustable Coil-Over Kits
All-Season Performance Tires
Camber/Caster Plates
High/Maximum Performance Tires
Shocks
Springs
Strut Tower Braces
Sway Bar Bushings
Sway Bar Links
Sway Bars/Anti-Roll Bars

Adjustable Coil-Over Kits

Adjustable coil-over kits take performance springs one step further by allowing you to adjust the height of your car. When the 1¼" drop from Eibach springs isn't enough, you can further adjust the height by a simple turn of the adjuster. This is much safer then cutting the springs, since you won't be losing tension strength. The more you lower the vehicle, the tighter the springs will become, reducing the chance of bottoming out. This can be very beneficial if you normally use your car for transportation, but like to race occasionally on the track.

Ground Control offers a set of coil-overs for all Probes. They come complete with a set of Eibach springs.

Personal Experience: My '91 GT is at the perfect height, so I don't have any interest in a Ground Control System for it. I haven't decided what I'll be doing with my '89 LX's suspension, but I don't think I'll be going low enough to need one of these systems.
Pros: Improved handling, adjustable center of gravity, less body roll, decreased vehicle diving and squatting, appearance.
Cons: Adjustments must be uniform for each wheel for optimum handling.
Cost: $350-400 per set
Manufacturers: Ground Control Suspension Systems
  Availability: All
 

All-Season Performance Tires
All-season performance tires offer the greatest wet traction/dry traction combo. Although they don't offer as much dry traction as high or maximum performance tires, they make up for it by offering good wet traction. Most also offer a very high tread wear rating making these a very tempting choice. This is the best tire for all around driving.

Good tires are an important part of the brake system as well. A good set will keep your car from breaking loose under heavy braking.

Personal Experience: After giving up on Goodyear all-season tires, I bought a set of Michelin X-Ones for my LX based on the high stats I read everywhere on them. The dry traction was incredible and the wet traction was easily the best I've ever had in a tire. Cornering, they gripped like glue.

When I got my GT, it had a good set of Goodyear performance tires on it. Even though they were 'performance tires' they broke loose every time the turbo would kick in. I looked looked into getting a set of high performance tires, but due to my overly satisfied experience with the Michelin's on my LX, I decided on a set of X-Ones instead. Not long after, I took an exit with a bit of a sharp turn doing about 100mph...leaving an '80s Camaro and a new Prelude who were trying to catch up in the dust. I would recommend these tires to anyone.

Pros: Better wet/dry traction, increased cornering traction, increased tread life.
Cons: None.
Cost: $75-$150 per tire
Manufacturers: Michelin, Pirelli, Goodyear, Yokohama, Dunlop
  Availability: All
 

Camber/Caster Plates

Adjustable camber/caster plates allow you to make quick adjustments to the front wheel angle alignments. Camber is the left/right alignment of the wheels, while caster is the front/back alignment. Caster alignment will do very little, if anything, for the Probe. Camber adjustment, on the other hand, will allow you to fix camber alignments outside of factory specifications. This is useful when the vehicle's been lowered. Lowering the vehicle can effect the camber angle of the tire, where the tops of the tires are closer together then the bottoms. This reduces the effective contact patch where the tire meets the road. Adjusting the camber after the vehicle's been lowered will return the tire flat on the road for best traction.

The adjustability of the camber/caster plates allow you to make on-the-fly adjustments. This is very useful when paired with adjustable coil-overs, which allow quick adjustment of the height of the vehicle. The vehicle can be lowered, then the camber can be immediately fixed.

The main problem with these are the adjustments themselves. Improper and unequal adjustments can cause unwanted effects, such as uneven tire wear and steering pull to the left or right.

Personal Experience: No interest.
Pros: Improved traction, quick adjustments.
Cons: Only useful if properly used, not for novices.
Cost: $250-300 per pair
Manufacturers: Ground Control Suspension Systems
  Availability: All
 

High/Maximum Performance Tires
High Performance and maximum performance tires offer the best dry traction available in a street tire. Unfortunately, with the minor dry traction increase over other tires, poor wet traction, and the excessive cost makes their value questionable. Most have very poor wear ratings. These are best for track only where every bit of improvement is necessary.

Good tires are an important part of the brake system as well. A good set will keep your car from breaking loose under heavy braking.

Personal Experience: I looked into high performance tires for my GT right after I purchased it. After looking at multiple stats on traction and performance of different tires, I decided on Michelin X-One all-season tires. The decision was due to the poor wet/snow stats high and maximum performance tires had, as well as their extremely low tread wear rating.

After a year and a half, I looked into tires again. I found that the Michelin Pilot XGTs had better cornering traction and dry traction without much of a loss in wet traction. They've been well worth the money and are noticeably better then the X-Ones. Tread wear took a nose dive to 300 from 620 though.

Pros: Best dry traction, increased cornering traction.
Cons: Poor wet road traction, low tread wear resistance, cost.
Cost: $100+ per tire
Manufacturers: Michelin, Pirelli, Goodyear, Yokohama, Dunlop
  Availability: All
 

Shocks
The shocks are the main culprit of body dive and squatting and are an important part of how the car handles. The GTs already have good shocks and great handling. Upgrading the shocks on GTs may be a bit too harsh for many drivers. Non-GTs have a bit of room for improvement.

Upgrading the shocks will produce stiffer handling and considerably better cornering control. Although this may be desired by performance enthusiasts, this can lead to worsened performance from your car. If your car's shocks are too stiff, even minor bumps can cause it to bounce easier, which will cause it to loose traction. For example, under heavy acceleration, the tires need all the grip they can get. Softer shocks will allow the tires to go over a small bump without loosing traction. If stiffer shocks go over a bump, the tire is more likely to lift from the ground, reducing the contact patch between the tire and the ground, which can cause the tire to loose its grip on the road. You should consider the pros vs the cons on shocks before upgrading, especially if you area has poor roads.

Personal Experience: I always preferred the first generation GT's Programmed Ride Control function. Replacing the OEM shocks with aftermarket shocks would disable the PRC, so I decided to just buy a new set of OEM shocks when I got the Eibach springs.
Pros: Improved handling, less body roll, decreased vehicle diving and squatting.
Cons: Harder ride.
Cost: $75-$175 per shock
Manufacturers: Koni, KYB, Tokico
  Availability: All
 

Springs
The OEM springs on the Probes are actually quite good. They offer good cornering control and minor body squat and dive. They're good, but there is room for improvement. Upgrading the springs is more for the performance driver since aftermarket springs would be too tight for the average driver. Aftermarket springs offer greater spring strength, reducing squat and dive. Most also offer shorter springs lowering the body by as much as 1-1/2", lowering the car's center of gravity, which improves handling and appearance.

There's a procedure where some people like to lower their cars even more by cutting the springs down. Stock or aftermarket springs should never be cut since their spring weight is directly related to how high they should be. Cutting down the springs can cause the car to bottom out on heavy bumps or cause major damage to the struts.

Personal Experience: Bought the Eibach Pro-Kit for '89-92 Probes for my GT. Installation was basically easy. No problems installing. It took about three weeks for the springs to break in.

Diving and squatting when accelerating and stopping was greatly reduced. The 1-1/4" drop makes my GT look more aggressive. The bumps seem a bit more harsh, but overall ride quality is much better. Handling is tighter, but corning seems only slightly improved. The biggest problem is the bottom of my front bumper scraping the ground when I pull straight into my driveway.

Pros: Improved handling, lower center of gravity, less body roll, decreased vehicle diving and squatting, appearance.
Cons: Harder ride, less ground clearance.
Cost: $200-$300 per set
Manufacturers: Eibach, GAB, H&R, Suspension Techniques, Tokico
  Availability: All
 

Strut Tower Braces
Hard, high speed cornering can cause the body of a car to twist. During the twist, both sides of the car will move slightly in opposite directions... one side slightly forward, while the other moves slightly backward. This compromises the structural integrity of the car. Strut tower braces lock the two sides together, greatly reducing longitudinal twisting. A strut tower brace connects the left and right strut towers together adding strength to the body and giving the car a more solid feel during corning. Adding one to the front and another to the rear can greatly improve your car's structural integrity, and will keep the distance between your strut towers from from increasing or decreasing, reducing possible misalignment.
Personal Experience: None
Pros: Strengthens frame, eliminates longitudinal twist.
Cons: Rear brace will limit trunk space.
Cost: $50-$300 per brace
Manufacturers: Freedom Design, GAB, MazdaSpeed, Road Race Engineering
  Availability: All
 

Sway Bar Bushings
Stock sway bars and even some aftermarket sway bars include rubber bushings for mounting. These bushings, even hardened rubber bushings, can move a bit under force. Heavy cornering can benefit from stronger sway bar bushings by being limited to the amount of movement allowed by the bushings. Most bushing upgrades are made from polyurethane which has very little allowances for movement.

Although there aren't any direct fit kits for the Probe, most universal kits can be used.

Personal Experience: No interest.
Pros: Improves effects of the sway bars.
Cons: A bit harder ride.
Cost: $10-$30 per set
Manufacturers: Energy Suspension, Herb Adams, Prothane
  Availability: All
 

Sway Bar Links
Sway bars are only as good as the links that hold them to the suspension. Even new factory links can yield some flex in them, lessening the effects of the sway bars. Unfortunately, it's somewhat difficult to find any performance manufacturer that offers sway bar link upgrades, but most standard replacement links that you can get are actually upgrades over factory equipment. Many are thicker and stronger then the factory links and have tougher bushings that can support the improved sway bars.
Personal Experience: I purchased a set of Energy Suspension links for my '92 GT. Simple installation with a couple of wrenches. They offered a slightly more riggid suspension for the front and rear ends.
Pros: Improves effects of the sway bars.
Cons: None.
Cost: $5-$10 each
Manufacturers: Beck Arnley, Energy Suspension, McQuay Norris
  Availability: All
 

Sway Bars/Anti-Roll Bars
All Probes have a front and rear sway bar. Sway bars reduce body roll during a turn while controlling understeer and oversteer. Understeer is when the front tires lose traction during a turn at high speed. The car will begin to straighten out, causing its turning radius to become larger. Oversteer is when the rear tires lose traction during a turn at high speed. The car will begin to head more sharply into the turn, causing its turning radius to become smaller. A larger bar in front will increase understeer, while a larger bar in the rear will increase oversteer.

All Probes have a moderate amount of understeer and very little body roll. Aftermarket sway bars will even out the suspension while reducing body roll to a minimum allowing maximum speed and control throughout the turn.

Personal Experience: I bought the Eibach AntiRoll kit for the '89-92 Probes to install on my GT. Overall installation was pretty easy. Due to the limited space, the front bar was a bit tricky to remove the stock and install the new. It included removing the exhaust pipe under the engine and disconnecting the steering knuckle from the strut in order to swing it forward. The rear was much easier to install, but the bushing supplied to me for the rear were too big and required shaving off 1/8th" off the base.

Body roll with the stock sway bars was minor. With the Eibach bars, the body roll was reduced to almost nothing. Severity of road bumps was increased a bit, but it's outshined by the overall better driving feel.

Pros: Decreased body roll, improved handling.
Cons: Harsher ride.
Cost: $150-$200 per bar
Manufacturers: Addco, Eibach, Suspension Techniques
  Availability: All
 

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