They play a BIG part on a cars handling. Why do different paper air plains handle differently? They are smaller and lighter than RC car bodies. Try taking off the rear spoiler on a Stratus body. Or any body for that matter. Your car will more than likely be very loose. And about real cars... I think aerodynamics can be felt at lower speeds as well. Especially if you can draft at 60mph... or a bus or truck at 35 can pull in a cyclist goin by. Anyways as for the other bodies, I think as long as you have a descent size wing, you should be just fine.