They're very clean burning 2-stroke fuel injected mostly now, but four strokes are coming on strong as they're heavier but the turbos are really making them extremely fast and fun to ride. Looking forward to try and one of the four stroke turbos. But for now the two-stroke has so much power write-off and holds it to seemingly no end. There's plenty of inclusive snowmobile packages that even look like a lot of fun for someone who has a snowmobile also.