I do know that in the races these cars are designed to compete in, the top teams regularly run at the speed limits: 130 km/h in the (Australia) World Solar Chal

I do know that in the races these cars are designed to compete in, the top teams regularly run at the speed limits: 130 km/h in the (Australia) World Solar Challenge, 65 mph in the (USA) American Solar Challenge; not sure about the South African or Japanese races. If for some reason Guinness doesn't have that recorded, then perhaps one of the competitors in those races should invite them? e.g. http://en.wikipedia.org/wiki/Tokai_Challenger http://en.wikipedia.org/wiki/Tokai_Challenger or http://en.wikipedia.org/wiki/Nuna_5 http://en.wikipedia.org/wiki/Nuna_5