Small prototype ?

I was figuring when DA-11 gets 125 mph on 18 hp ( with limited pilot size ) I think a 140 mph speed should be reached with heavier pilot if aerodynamics were even more refined. This craft would be a downsized model for the 3-4 seater with 80-100 hp engine. Having a 30 hp B&S tuned for 50 hp with a new carburettor and some fixed inlets. DA-11 is 170 lbs I figure the 80 lbs engine and some new aspects would still keep it ( new design ) in 160 lbs. Red lining would occur at 220-230 mph.