I ride an 04 f4i and found a smokin deal on a 520 conversion kit. Watch for these kind of deals they are too good to be true. RK x ring chain and vortex sprocket. EEGH. Warranty on the first on after 5k miles and the replacement is now gone after about the same, 5k miles. Went up 2 teeth in the rear and down one in the front as well as all of the saved unsprung weight by going with the 520. Performance was way better, but eatin up sprockets on an f4i? Mind the line between performance and excessive wear. If you dont mind spendin 150 bucks 2 maybe 3 times a year. (Depending how much you ride) do the cheapie conversion kit. I think the store was sumofallparts.com or .net maybe .org? Otherwise steel sprockets and the 530 are the way to go. Oh dropping one tooth in the front and going up 2 in the rear cost me about 15 - 20 mph. top end. It wouldnt redline in 6th before switching ratios.