Once installed we evaluated the ACT HD clutch and flywheel. The clutch engages in normal driving very nicely. It is very smooth and engages without chatter. There is no perceptible increase in gear rattle as often tends to happen with lightweight flywheels. The clutch also grabs well at higher throttle and RPM levels.
The acceleration is improved due to the light flywheel but it is not a huge difference because the AP1 flywheel is pretty light to begin with. We figure on an AP2 with a much heavier flywheel, the difference would be much greater.
Due to the light flywheel, shifting is improved and rev matching on downshifts is a lot easier. The XACT Prolite flywheel is pleasant to drive and very streetable even though it is sold as a race part. ACT also has a heavier flywheel available, but we feel that it is ok to go straight to the lighter model even if the car is a daily driver.
The only slight negative issue we noted is that the clutch pedal effort is pretty noticeably increased over the clutch that was in the car. That clutch was a no name aftermarket stock replacement clutch so who knows what its rating was, but the ACT clutch pedal is about 50% stiffer. Normally on other cars we have tested with this same clutch combo, the clutch pedal effort was marginally changed.
Perhaps this is because this clutch has 39% more clamping force when typically the ACT HD clutch has a 20-25% increase in clamping load. Perhaps the clutch that was in the car was fatigued or speced on the light side. The clutch pedal is firm, but not overly stiff for daily driving, it's just stiffer than what we expected.
Overall the ACT HD clutch and XACT Prolite lightweight flywheel are a great upgrade for those who have an S2K with moderate power increases that are daily driven. The HD clutch is easily up to the diametrically opposite tasks of hard track driving and being smooth and comfortable on the ride home. We can honesty recommend this combo any day.