I'm with Jason on this, I too have the HRC stage 1 and the turbo starts spooling between 2600-2800 rpms. No problem with the turbo not spooling pretty quick but maybe it is because of the compression difference. I don't know, but my experience with the HRC kit with the super 16g on my 420a has been amazing, not on a 4g63 engine so I don't know. I love the HRC kit and I definetly support HRC. They have taken the most time to research our engine to its fullest potential. They have been one of the first comapnies and probably are still the only company to listen to us non-turbo DSMers cries for speed. Instead of hearing the one thing we all dread "sell it and buy a turbo model" they took the time and invested in all of us. But hey, it is a case by case experience, but in my experience its thumbs up!!