You might get someone to help you to change the landing gear configuration. If you could eliminate the nose wheel and move the main gear so that the wheels' axles are at the leading edge of the wing (plane level) and mount a tailwheel to the rudder these modifications would reduce the ground and airborne drag and lighten the airplane a little. This small weight change will improve the performance, too! It's a little 'testier' learning to take off and land but once learned- never forgotten. The next thing to consider if the prop/ wheel changes don't help and you don't want to modify anything is a larger engine. I'm partial to the 4- strokers. You will most likely want another airplane and an engine on hand dictates your choice in airframes in many cases.