How fast are you going, anyway? Area ruling is only helpful for aircraft in the highly compressible regime, i.e. transonic. The whole idea of area-ruling is to reduce the transonic drag rise, and delay the drag-divergence mach number. By their very nature, propeller aircraft can't usually get up to this level.

The biggest, best thing you can do is clean up and reducethe area that's in the propwash. "Scrubbing" drag is a tremendous factor in aircraft speed, as the small, high-rev racing propellers are moving the propwash at very high speeds. Get the area of the fuse down by decreasing the cross section, move the tail back farther and make is smaller, all of the things you see on the Formula 1 full-scalers. If you can come up with a way to cool it, properly cownling the engine would be tremendous boost.

.02 deposited.