Have you purchased this kit yet? When you talk to RC about the kit, tell them the wheel you are using. I believe that they have two different sizes of rotors they provide.
Yeah, but anything under an 11" rotor is downright inneffective in these cars. It's not the rotor size either, the stock KH setup was 11.25" and fit under 14s.
BUMP
PS: If it comes down to that, I'll find some wheels