I have an 08 dragon, it was a 155 and I put a 163 under it. I have had some issues with my sled, nothing to do with track swapping, but I have had some motor issues. I had the 2010 update done on it, so its got the double ring pistons and new head. Even though I did the update I went ahead and bought a Power Commander V for it and let me tell ya, really woke the sled up. Reason I put it on was to eliminate the chances of finding that lean spot and taking the rings out of it. Happened to me once!! The other thing I just did to it this year was do the airbox update on it. Timbersled makes the kit, seals the airbox and puts a K&N air filter on top so it eliminates the engine from sucking it the belt dust and taking your motor!!! That also happened to me!!! But all in all, its been a good sled!! I ride the sh*t out it and have lots of fun. But if I was going to buy another one, I would do those two things to it, the PCV and the Air Box Kit. I'm sure your sled will be good for ya, just something to think about!!!