Interesting discussion. Just to add one more data point to the mix; I've been running an ACT HD plate with a 4-puck disc in the 240SX since I put the new engine in back in '07. Granted, I only run a few events per year, so I probably have only 15-18 weekends on the engine since then, but so far I have had zero issues with the clutch or tranny (having said this, I've probably guaranteed that both explode the next time I go on track...). The engagement doesn't feel any more harsh than the oem clutch did, in fact about the only time I notice any difference is when driving around the paddock in 1st gear. I can slip the clutch just like the stock one when putting it on/taking it off the trailer, and on track I can't tell any difference (other than it doesn't start slipping after 15 mins...). I won't hesitate to use the same disc again when it's time to freshen up.