I've flown mine with a Supertigre GS40 to a rear exhaust .60 pattern engine on a tuned pipe! It really doesn't matter. Run what you have, or just buy a .46-55 since that will give you more options should you want to use the engine on your next plane in the future. For me, the Supertigre 40 was my favorite since it still had unlimited vertical and on the straight and level I could run full throttle all day and it wouldn't flutter the ailerons. The larger engines this was an issue.

Mike