To get more power yet with the same mods simply get ProTuned.. I would not do a header, get the stocker Ported and Polished (caoted) and a High flow cross over pipe. Upgrade to a GM boost ssolenoid (or equal). Silicone Turbo inlet wouldn't hurt.. Upgraded TMIC or upgraded "Y" Pipe, I would lean towards new TMIC.. One can always Porting and Polishing stock turbo with upgraded 19T compressor wheel (Blouch Turbo)... Not to mention Porting and Polishing Throttle Bodie, Intercooler elbows, Up-Pipe... TGV deletes (ported and Polished).. UPgrabded Fuel pump wouldn't hurt either.. Pinks for growth, don't wanna max them out.. There are so many little things that can add up to power..
02 WRX.. "It's fun when it runs.. Problem is that it hardly ever does..."