I don't race mine as much as I would like, but as Tom will assure when I do, I go all out. I haven't had any issues with my pulley so far...this first one that I recieved did rub, and was immediately replaced, no hassles at all...as for the other mods he sells, and others sell, they are racing mods, for the most part unproven, not tested for very long. So gentleman, its racing, its experimenting, those mods won't always work, nor will they always hold up until a lot testing miles are put on them. Rob has the right idea, test, test , test before you market, but many of you pressured him to get the manis out, and now there has been supposed problems with them...so, think before you jump...I watch and listen on here and wait for many of you chance takers to run the h@ll out them for awhile before I buy... just my observation