Just a couple of notes: You have a 2005 and Flyboy has a 2001. There is no Dinan S2 "package" available for 2004 and newer E53 models. That's because Dinan never released TRANSMISSION software for the 2004 and newer X5s. They have ENGINE software, but not the TRANSMISSION SOFTWARE. So the bottom line is, you can still do all the mods that Flyboy has, but you need to ask for them a-la-carte: 1)Throttle body, 2) free-flow-exhausts, 3) Stage 3 ENGINE software, 4) strut bar. You won't need the CAI, becuase you've already got the AFE one, which is probably no worse than the Dinan one.