Here's a summary of the mod pasted from VFAQ.com:
Power Steering Pump Cutout Fix FAQ
The idea:
Speed sensitive steering is a feature available on many different cars. Its job is to give the car a more stable and heavy feel at highway speeds, and to make the car less prone to sudden changes in steering angle at speeds where such a move would be dangerous. It also allows more steering assist at low speeds for parking maneuvers.
The Problem:
Speed sensitive steering is great, but that's not what our 2L (Turbo&NA) DSMs are equipped with. We have RPM sensitive steering, which acts somewhat the same. It will decrease the steering boost at highway speeds because the engine is turning 3500-4000 RPM, but unfortunately it severely cuts the steering boost in the upper-rev range, regardless of what gear the car is in. 6000 RPM through an auto-x slalom results in minimal steering assist, followed by a sudden lack of any assist. Not exactly what an auto-x driver is looking for.
The solution:
The steering assist reduction is caused by a valve in the power steering pump itself. We will be adding a spacer to preload the spring inside the small assist varying valve that closes at high RPM. This will stop it from restricting the flow of PS fluid out of the pump at high RPMs, but will not raise the maximum pressure of the fliud leaving the pump.
Some people have in the past shimmed the flow bypass valve in the pump. This is a separate assembly that sits below the assist varying valve. This resulted in more steering assist at high speeds, but accomplished this in a bad way. The flow bypass valve is there to relieve the high pressure created when the pump spins faster (high RPMs) and the flow exceeds that which is needed by the power steering system. If you shim this valve the fluid has nowhere else to go, and its pressure will increase far beyond the factory levels. I tried this, but after a 15 minute drive at moderate speed my fluid boiled and I lost steering assist. Not good.
