I have a 98 Integra with around 133k on it. I have only had to change the brake pads twice. Once at around 60k and once at around 110k. Recently I have noticed that at highway speeds 60+ mph thier is a very noticable vibration if I hit the brakes. Enough to shake the cups in my cupholder. It seems to be coming from the brakes. At low speeds I notice nothing. How do I tell if my rotors are warped?