There is a fellow who posts on RCU that files an Edge with a 120 4-stroke Magnum. he says it performs well, I think his handle is "cootertoo".

I think the Edge would be a better plane for a big 4-stroke as I think they are still using 1/4" birch ply for the firewall and landing-gear plate. These components are made from lite-ply on the Extra. This was my only dissapointment when I had a look at my plane when it came in. From the web-site I assumed that the Extra had birch ply in these areas.