JSVT, about the 73mm MAF, I believe it is holding you back. My experience with it is with my SHO, but still the POS 73mm as I refer to it as. my SHOs bottom end I believe suffered from the 73, but the top end was killer.
As for the spring rubbers, i tried them on my first time to the track with my car. haven't had them in since, but I'm going to next season.
