We've sold a bunch of these. We've had a high success rate. However, I won't play any sales tactics here, every clutch company has a "Bad reputation". The reality is the manufacturer does come into play some of the time, however, if you dig deep enough into each individual case, more times then not, it stems from a bad install. But I digress, if there is one thing about clutch kits people should realize is any aftermarket choice is a gamble.
If you are willing to make the power then you need to be willing to sacrifice on some aspect of aftermarket clutches. We got a bunch of guys with basically tune only cars, full bolt ons, and some single turbo guys that are extremely happy with these clutches. Not to mention a good portion who now have the Spec Clutches originally had the ACT and were not happy with it at all. Either the low engagement point and or the longevity of the clutch steered them away from a 2nd purchase.
If anyone has any questions, let me know.
We have a very nice FAQ in our clutch section for the BMW 135i 335i about Spec Clutches and how to choose the best one for you.
In a nut shell if you plan on making over 500WHP we suggest the single mass steel flywheel, as the OEM DMFW has been causing misfires due to an imbalance at high HP.
Otherwise we recommend anyone in the regular bolt on territory to stick with the OEM DMFW, and we highly recommend a new one as resurfacing them improperly will cause problems and not many shops can actually do it right.
The aluminum flywheel chatters more then the steel flywheel single mass options. Our FAQ also mentions in detail what comes with each specific clutch kit. I'd post a link but we are not allowed to here.
BMW>335i>Clutch kits> (On our site)