I have the MSD 6AL box, billet distributor, and coil in the Fastback. Everything has been great so far, but I really appreciate the rev limiter feature. The Centerforce clutch has also been flawless for typical street driving. However, recently, (500 miles since since competion) I figured that it was time to wring things out a little. That's when I found out the the clutch pedal stuck to the floor between the 1st to 2nd shift somwhere between 5000 and 6000 rpm. The feel and action of the clutch pedal was so good during typical driving that I hadn't removed the "over-the-center" spring (as some have recommended). Centerforce diaphram clutches are designed to reduce pedal effort as RPMs increase. In my case, the pedal spring overcame the clutches ability to return the pedal until the rpms dropped back down. The 6000 chip in the rev limiter kept the engine under control during this situation which, otherwise, could have caused excessive rpms and associated damage.