I'm looking into getting back into Subaru as well. I had an 04 WRX and after pricing out an STI swap and all the labor it just wasn't worth it, I sold the WRX and bought an 05 STI. When doing an STI swap into a WRX you will need the complete wiring harness, all the ECU's gas tank and dash. Don't forget the little things like radiator as they are different from WRX and STI.