They are very good engines. If you want one to get a hop up job then Clarence Lee is still working on them. You can find his adds in MAN. Great person to deal with too. It's one of the over looked engines and well worth the money. Looking cool isn't any way to look at it. I like the SK line of engines sold through Kangke and they aren't polished at all, they just run good. I only say that about the .90 because it's the only size I have used though. After several of them I like them better then the OS.