Well if you can keep the weight down- (DON'T use 21st Century Fabric !! ) I would suggest the US 41cc with the Bennet muffler- it was a nice fit and they can be bought used for $175 or less, originally I flew with the 41. but after the rebuild it gained 2+ pounds mostly from the 21st
century fabric- It barely flew afterwards and I put in the G62, removed the 41 and 1 lb of lead in the nose- Haven't flown it since the G62 was installed though