Hello me and my dother playd before, with both controlles on and one profile, and we both can turn and breake with both controlles, not so god when i play in carrier and lost 
This has the potential for some fun, sort of like those figure 8 races where they chain 2 or 3 cars together with 9 me controlling the gas and steering and the other controlling the brake or whatever other combination.
This sounds awesome! You have two people on one controller each, and one of you has to finish a race, the other has to wreck the car. lol