Not trying to hijack this old thread, but I want power and fuel economy when needed, I keep hearing turbo sleds get good fuel economy 15-17, my 15 viper ltx dx with 1.6 ice cobra, ulmers intake big venom clutch kit and sandale can would get at least 13 ridden hard on 87 Oct, saw 16.4 once on -18 day with perfectly groomed trail's, now with Evo stage 4 flash and straight line header , can barely get over 11 on 91 Oct, plenty of power down low but sled still seems to hit a wall at 84-86 mph, sounds like the 21-41 gearing would help some in the mileage dept , probably going with mpi turbo 190 kit, I'm happy with the power of my setup now, just not economy and top end.