i would highly recommend water injection with an appropriate nozzle size for whatever injectors you run. i would also suggest that you have a sturdy set of gaskets and your car tuned to high boost. you may have to redo your whole exhaust system from the heads to the test pipes to make it work with an external gate and hold that much boost without disturbing the flow of your exhaust. you do not have to run huge gates if you are going to be running a lot of boost most of the time. a single water injection nozzle in the intake elbow of a 4g63 will clear almost all knock up to 23 psi on 91 octane. running a little more alcohol in the mix and haveing two throttle body or i/c pipe nozzles should clear a lot of knock.