When it comes to turbo upgrades, always know your goal. A big turbo is going to net you big gains IF it spools up. Also, depending on your turbo combination, you are going to get different spool times, and the efficiency of your turbo is going to vary. I advise that you study the compressor map first before making any choices.mcocozza said:This request is more for information/interest vs. actually planning on implementing - but; are there recommendations on Turbo replacements? I thought that I'd seen verbiage talking about getting the STI to 450 hp.