The 160 can produce some serious vibes. It's pumping out close to 4 HP. If your going to use it I'd go with the best engine mount you can get. Again,, .... if your going to mount it inverted ,,, and you'll have to so there will be some cowling left to look at. You may run into some trouble with starting and reliability issues. The OS160 may be a good choice for some warbirds. But you'll be using the Pitts muffler on a sleek fighter like the Spit I would think. Stock muff is HUGE. And from experience I can tell you that all will seem great until you've been flying for a few minutes and it dies suddenly and for no reason. Then your driving a 12 to 13 LB warbird without any prop wash under the wings.

Besides the 2 stroke forum you might do a search in the Pattern Forum. The 160 was used quite a bit by these guys for contests before they mostly switched to the YS 4 strokes. And I believe they mounted them mainly inverted as well because of the narrow cowlings on the Pattern Ships. 4 Strokes don't seem to mind being inverted as much as a rule.

Last thing,,, and I hope Richard and others will add to this and back me up. The OS160 topic is a giant mixed bag of fans and enemies here in RCU. My advice is read everything you can about them and make your decision based on specs and veteran RC'rs advice.