he would lose his license and have the car siezed.
he would then rent a shop and work on his Cadillac after getting it out of impound.
instead of putting the car back on the street he would cut a few hundred pounds out of it, mod the crap out of it, apply every trick he gleaned from Gran Turismo and then proceed to enter the car in a regional racing series, win every race he finishes in the first year and win the whole thing his second year out… then upgrade out of a cadillac into a space ship.