pretty much any aftermarket HU made in the last 4 or 5 years will withstand harsh road conditions. most aftermarket headunits we use can withstand upwards of 150dB in the car and i think the vibrations from that are more harsh than a bumpy road.
on a side note cool car. i just hope you race it at the track and not on the street. since street racers are ignorant and should not be allowed to breed.