You guys are misunderstanding me. The bottom of the motor guard has a tab that rests on the chassis. If you look close there is a .05 shim with a slit in the middle. You can remove it. Just like the rb5, the manual says to add a .05 shim between the motor guard and the hangar. So in all, thats two shims in the rear. I showed this shim to two other people at my track and they were both unaware it was even there.