Just for interest sake. My son pulled the valves on our 18 High Country 8000 with 4200 Km’s on it.They we’re absolutely perfect no carbon or any debris of any kind. it has had only C tech for oil and high test fuel. I think this just proves the point especially when this sled has lived at least half its life at max rpm’s while playing in the deep stuff. So if it works why chance something else?