The RS5 body design with 2 rear body towers, compared with RS4 body is wider and longer it make RS5 body more stable and easier to drive especially on the indoor carpet tracks.
The RS5 body comes 3 different thicknesses body shell. The lightest is 0.4mm, is recommended for use at a high traction track where the car has a chance to traction roll.
The 0.5mm body works at all conditions because the body shell is harder so it can transfer more downforce to the chassis and increase overall traction.
The 0.7mm body shell is heavy and strong, and it is recommended for drivers want a very stable and long-lasting body shell.