It is a great plane. You will enjoy it very much. My plane has an OS Max 61 with a Slimline brand Pitts muffler. It sounds good and the power is great. The plane balanced with no lead what so ever with this engine. But you can always move your radio equipment forward or aft to balance the plane regardless of your engine choice.
I know everyone is sick and tired of seeing my Chipmunk, but I just can't help myself, sorry.