the working gear (cassette+chain) on my blur after 6 months is starting to look a little tired. rather than replace just the shimano XT chain and cassette i'm considering moving to sram. cables are replaced every month or two. hubs are onyx, truvativ cranks, xt derailleur and shifters. what components do i have to change to go to sram. i'm not adverse to using XT it's just i've ridden shimano for 2 years now and looking to test the competition. help appreciated.