Just to answer a couple of the questions: Since this was 1 year ago - I went with the McLeod RST (up to 800HP version) as I do not intend to modify, or certainly not beyond 800 HP. Based my brand decision on: preference of the shop doing the work (important!!), and CUSTOMER SERVICE/input from McLeod, Spec and Centerforce. Mcleod was the most responsive to my emails, and I got the feeling they would be the best to deal with after the sale if needed. Mcleod also offers a rebuild service on their units- not sure about the others. Super happy with it, but have only put about 4k miles on it since. I adhered to the recommend break-in (!), and have been fairly easy with it. One nice, noteworthy difference was that (at least in my case)- the McLeod takes MUCH less foot pedal pressure on the clutch pedal than the stock unit- so much so that I went back into the shop before leaving their parking lot to ensure all was "ok". It's a nice difference in using less leg strength to engage the clutch (haven't heard that from anyone else- maybe it's just mine?). IMHO - it's hard to judge which is best (McLeod, Spec, Centerforce), because install can affect performance, and we all have a different idea of how bad we should be able to beat on something before it breaks. There are too many variables to easily say which is best for you. I'm sure most of us think we're expert drivers and "shift like the Pro's" :-), but I admit that I'm an average guy that is fortunate enough to own an extraordinary vehicle.