After 30yrs on the same brand I will be buying my first cat(T660) and I have some questions. What is the difference between the act drive + driven clutches vs artic rpm sensing + arctic roller cam? Are they interchangable? Whats the difference aws V vs aws V1? How bout fastrack long travel system slide rail with coupling blocks vs no coupling blocks? And (just outa curiousity) blow molded plastic vs plastic? Thanks. Btw, if your up in the air about the performance of the T660 don''t be. I drove one and was very impressed, a little heavy in the front but I think that can be fixed. I did 4500mi on 800xcsp this year and expected a huge difference in power on the T660, there was a difference but not even close to what I expected.