Brake light standards are set by the DOT. You stand a good chance of legal action in certain circumstances if you try over powering brake lights or any exterior light on a motor vehicle.
It is legal to have more than one DOT approved brake light on each side of a vehicle's rear end but the candle power(lumens) must fall into a certain set of parameters as must the lens. For tailgaters(and it is unlawful in most jurisdictions) what I do is I maintain my speed and turn on my four ways for a few seconds. I repeat as needed to get the jerk off my a##.