I'm interested in any responses to this question. Since there are none, I'll throw in my two cents.. I think the use of the tractor will help determine the clutch need. If it is in a severe service such as loader work with lots of direction changes, lots of start/stops, etc, maybe the wet clutch would be justified. Just remember it'll cost more to replace when it does go out. My opinion is that for mowing, plowing, and other uses that don't require constant clutching a dry clutch is fine as long as it isn't ridden and kept adjusted.