My Spec stage II let up after 1600 miles with only a few days of track use and mostly being driven on the street. It was properly installed with a resurfaced stock flywheel. I would not get another. I will say that the pedal pressure was less than a stock turbo clutch, which was nice.
I now run a Fidanza flywheel with an ACT HD PP and street disk. Pedal pressure is higher than the stock clutch, but not much. I could not be happier with this setup. The engagement at first was down by the floor, but after 500 miles it is in the middle, more or less. No grabbiness, really smooth engagement and easy to drive on the street. I have not taken it to the track, yet. It is rated for 400ft lbs which is plenty for me. My car is only around 270ft lbs. I would definitely recommend this clutch/flywheel setup.
Aaron