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Positive Steering Response System for 2002-07 WRX/STI


2 Hours

Part Numbers
PSP-SUS-402 = 02-05 WRX
PSP-SUS-403 = 04-07 STI, 06-07 WRX

WARNING: This product can expose you to chemicals which are known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to

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Improve turn-in and increase handling proficiency with the PERRIN Positive Steering Response System.

What is PSRS?

P.S.R.S stands for Positive Steering Response System and simply replaces the front control arm rear bushings. The OEM bushings are designed to be extra compliant to reduce NVH, and make the ride more comfortable. The compliancy of this bushing is not something a performance oriented driver is looking for. Eliminating the OEM super soft bushing provides significant improvement in how the car steers during hard cornering and even in a straight line.

OEM Bushings - Bad

Under braking and acceleration, the OEM bushing can flex enough for your wheel to move back and forth .500"! This deflection of the wheel causes drastic toe in and toe out changes under braking. The toe changes will cause steering wandering and an altered tire contact patch. When accelerating, this OEM bushing causes unwanted wheel hop and the car will want to follow the ruts in the road.


After the PERRIN PSRS is installed, under braking the wheel will have zero deflection. Since there is no way for toe changes to occur, the steering feedback issues and wandering under braking disappears. Under acceleration the car will have far less tendency to follow the ruts in the road, wheel hop will be eliminated, and in turn the car will have more front-end traction.

Adds Caster

The bushing in the PSRS is purposely offset from center-line. This adds approximately 0.5 degrees of caster to the front suspension. Caster is the angle on which the steering knuckle rotates. Adding caster makes the car turn in faster by providing a larger contact patch as the wheels turn on the steering axis.

"Anti-Lift" Reduction Feature

A byproduct of the PSRS kit is that it reduces some of the built in "anti-lift" that Subaru builds into the suspension geometry. Changing the geometry toward a Pro-Lift setup which means there is more weight transfer happening under acceleration and deceleration. During acceleration this helps transfer weight to the rear of the car creating additional traction for the front tires, which reduces understeer. Same thing happens under braking.


The PERRIN PSRS features custom made Polyurethane Bushings. We choose a stiff 95a durometer material to provide a feel similar to a solid bearing bushing but without the harshness or noise that can be associated with them after years of use. Polyurethane is extremely durable, nearly maintenance free and less expensive than bearing type bushings. PERRIN polyurethane PSRS's were designed for those living in climates where your vehicle is commonly exposed to corrosive elements. The combination of aluminum, polyurethane, and yellow zinc plated hardware make PERRIN performance PSRS's very weather resistant and unaffected by wet climates and road salt. Polyurethan bushings will also transmit slightly less noise through the chassis than more rigid mediums.

Grease Fittings

The PSRS uses Zerk grease fittings to feed lubricant to the joint without the need to disassemble the PSRS. Grab your grease gun, and grease away!

5 Year Warranty

PERRIN Performance warrants to the original purchaser that all PERRIN products will be free from defects in material and workmanship within a sixty (60) month period from the date of purchase. *Some exclusions apply
» Read Full Warranty

Jeff's Blog

Learn in-depth about the PERRIN PSRSs and exactly how they operate and perform.
» Learn More


Warranty Details

This product features a 5 year warranty Read Full Warranty

Tech Department




Meterial 6061 Billet Aluminum
Finish Yes
Bushings Delrin (Polyoxymethylene)

Compatibility Detail


1993-2001 Impreza Yes
2002-2007 WRX Yes
2004-2007 STI Yes

NOTE: Offset PSRS will push front wheels forward on car roughly .500"

In The Box

In The Box

(1) Set of PERRIN PSRS bodies
(1) Silicone-based grease packet
All necessary hardware


Shipping Information

  • Item Requires Shipping
  • 4.0 lbs.
  • W5.0000” x H7.0000” x L11.0000”
  • This item ships in its own box.