I know I have a lot of friends who bought Clutches From Advanced Clutches and as in all racing situations a person has to buy the whole package and they all tell me the owner knows what he is talking about . I do know that there is a special bearing for advanced clutches that must used , oh by the way I know that there is and never has been a warranty or guarantee on any racing part . I talked to some customers of advanced clutches and without a doubt the owner is one of the top authorities on racing clutches and is fair to 90% of his customers they other 10% have burned up their clutches by not listening to advanced clutches advice