Now we've reached a point where your horsepower might be greater than stock by more than 100. If you have a WRX, your factory clutch is probably slipping pretty badly by now. You'll need a tougher one, probably with a stiffer pressure plate and a more heat-resistant friction surface.
While you have the tranny off the motor, you might want to choose a lightweight flywheel (as shown here), which allows the car to accelerate faster in low gears. There's a little sacrifice in slow-speed driveability, but it's not bad. There's also a little sacrifice in your cash flow, but hey, you knew that, right?
ACT clutches, like the one pictured here, are our most popular clutch packages. Exedy also makes excellent clutches -- your stock clutch was made by Exedy. For most cars the Exedy stock-replacement clutch is going to be your most affordable option, if your car has stock or near-stock horsepower.
Note that the STI has a more robust stock clutch than the WRX. Usually the factory STI clutch can withstand torque numbers that greatly exceed the point where the WRX clutch would have let go, but even the STI clutch has its limits. When the clutch starts to slip under power, it's time to start looking for something stronger.
Check out our clutch and flywheel offerings.
Now that we're done with medium-level modifications, it's time to step up to the next level. We call those extreme modifications. Are you ready?