Please save your money, and only buy a spec 3 or spec 3+. One of the best clutches you can buy, just ask any tranny shop, as they probably break more tranny's than any other clutch, as they rarely slip. You can only run a 10 spline, as no one makes a 26 spline for the 2005+ 3650 that I know of? You really don't need a flywheel either, as I still have the stock one, and I'm putting 500 wrhp down. However, it can't hurt. I broke my input shafts twice, so now I have a viper spec tr6060 six speed tranny.