We have been riding the new 2017 Ski-Doo Summit X 165″ and 154″ with 850 E-TEC engine and must say it was an awesome experience. So effortless and more fun to ride. It really feels like a new sled with better balance and better throttle response, and easier to flick around. Thanks Carl Kuster Mountain Park for an awesome experience. Photo Hans Wärdell Photography. Rider on top image is Carl Kuster. Rider in the image below is Rob Alford.