Having used both I think the wrap around is quieter, but the side mount has a couple of more rpm. All trade offs one way or the other based upon what you can deal with. I've flown all my Wild Hares with and without a cowl without issue. The open fronts have been closed and open without any noted differences. Flying without a cowl does make a significant difference in the way the plane appears on approach and alters your judgement a little. Sure makes it easy to access the needles, tho.