Went to d&d had them put in cluth kit, pipe, V-force reeds, bulles eyes in breather box, 170 studs and change spring on front schock in skid frame to give more tracktion and better ride through trails. I have F-7 standard with 0ne inch track. Sled ride great in trail, put on about 7 sleds maybe more in 700 feet. I have been using D&D set up for years they are the best, why do you think cat racer use them so much? I'm lucky I'm only 5 hours away I and I get them to install the stuff their not only nice guys but they know their bussiness well. If yopu want Fast and reliable call dan or dale teel what you have, what you want to accomplish. At this point listen and do what they say your friends will be looking at your flap like mine do.