I'm in the process of mapping out what I'll be doing for the car later this year. I know that along with a new bottom end I'll be replacing the tranny and fuel system. My ultimate goal is 550-600 RWHP and maintain it streetable (a/c, radio, etc). I'm currently running a P1-SC that is pushing 12-13#'s with a 3.30 pulley. Will the P1 be able to get me to the 550RWHP mark or am I going to have to upgrade it to the D1?? I contacted Procharger and they said that the upgrade would cost about $1000. It would obviously be best to send out while the car was down, but I want to know for sure that it's needed before I spend the money. I know that my goal will depend on other factors such as heads and cam's, so if anyone has any suggestions on combinations, that would be appreciated as well.