The measure of performance for any aircraft engine is power:weight. Just adding a tuned pipe and/or increasing rpm will put a stock G62 over a standard muffler equipped DA50 in those terms. We have handicapped our engines by using power killing mufflers and low operating rpm. The only measure thats left is displacement and weight, and that seems to be enough for most modelers. Generally the lite 50cc class are the best applied engine/airframe combos that are widely available. G62s always seem to end up on airframes that are too big and the owner's don't know how to get the power up, so they end up saying "my DA50 is more powerfull than a G62".