The way you tune with different bodies to get optimum handling is to get a few different bodies together. Get the car setup and comfortable to drive with a body you know you like. Then do the back to back tests to get a feel for what each body does to the car and make notes of it. If the Ride body gives a little more steering than the Mazda, and the car seems to push a little with the Mazda, run the Ride. The differences between the top race bodies are not giant, but they're enough to get you a couple tenths a lap if you're racing at a highly competitive level. And at that level, that can be making the A and being in the C main. So yes body selection can be very important. It's used for fine tuning the car. Many times it's used to compensate for track conditions. If you know it's going to tighten up in the afternoon due to heat, run a body with a little more steering. Now the handling difference between one of the top competition bodies (Mazda, Ride, Stratus 3.0 etc...) and a "basher" body like many of the HPI and Tamiya bodies that are more geared toward scale realism is HUGE. I wonder SOVIET, what body do you currently run on your TC? If you're running a competition body, go try out one of the HPI RX8 bodies with the stock wing on it. See how much of a difference you feel.