The BEST thing you can do to add a few mph would be, an open element air filt. go up 3-5 jet sizes, and get a malossi reed set (cage, and all). These parts can be had for around $50.00. A couple of fresh plugs will help get the jetting right. The next step would be spending some loot, on a jug kit, larger carb/intake system, and some serious time in fine tuning it all. Getting the cvt a fresh tune up is ALWAYS good too. The after-market parts are a very good investment if you want to do the full set-up, but not real important on their own.