The Sig Mustang 450 was hopelessly out of date by the time I was racing Formula One, so I never have seen one firsthand. By the late 80's, top F1's were pushing around 175 mph on the course, and some have exceeded 200 mph in longer straight line passes verified by radar. It just takes power, which 65% nitro burning 40's could produce at 27,000+ rpm.

As to wing strength, I could support the wings close to the tips and stand on the center section without a failure, and this was after some damage was sustained in a crash. Of course, I only weighed about 165 lbs then. The key to strength was 3/32 skins, 1/8 spar, 3/4 oz cloth, and 3 layers of 2 oz cloth of staggered widths at the center section.