thebluff: carb 2s engine is done at about 10,000 miles & new injected 2s if you get 10,000 miles you are the doing very very well. With carb 4s engines we are beginning to see 30,000 - 40,000 miles & still going strong but too soon to know about injected 4s but should be as good or better as carb 4s. The chassis seems to hold up all right need boggie wheels & tracks but lots of friction parts on sleds. Typical 2s sled engine nothing like your truck 4s engine. Rider forward to me is the single best reason to move up from older sit in sleds no matter 2s or 4s engine but no sled or engine built that goes 200,000 miles. That is why we want to move up before the big 2s engine meltdown in an old style chassis & have to spend big dollars on an engine repair. To me if you are are a trail rider buy a new or non current 4s sled & stay with it for 15,000 to 20,000 miles then move up to another 4s because it is lighter, has better gas milage, handles better... stuff like that. Boondockers don't put on a lot miles but operate engines at very high RPMs to stay on top of powder. Boondockers all about light weight, like 2s engines, long tracks & engine power. They tend to hit logs rocks ,stumps whatever is under snow & are more talented riders than trail riders. See skylar's post "the project begins" to understand how powder riders get ready for season & money they spend to keep their sleds going. Trail riders & boondockers very different interests both snowmobilers but want very different conditions for perfect day of riding. You get them both at the Bluff. I hope this helps....sometimes you are so deep in biz a rider is a rider just keep them happy staying at the Bluff.