Best shocks offered on the RMK. Also came with the 2.25 harder durometer track. The motors were known for grenading within 1k miles of mountain riding, both piston and cylinder skirts,. Takes out entire motor. A mix of injector issues, also, as the first year CFI2 800 was shipped with three different injector specs. Bulkheads would bend on hard impact behind the driveshaft, either side. Fix kits helped, but most didn't resolve the cylinder castings. I owned an 11 Pro, and did a motor fix before it grenaded, and was lucky with it, got out of it in 13 when the getting was good. If it was flat land driven, straight chassis/bulkhead, low miles, it could be attractive if priced right. Budget for a top end, regardless. Anything else is likely a project sled, and needs to be cheap. Best options are 14/15's in the Pro chassis. This chassis/motor changed everything for poo, but 11-13's could make alot of money disappear fast.