SPT (Subaru Performance Tuning) is Subaru of America's tuning division. STi (Subaru Tecnica International) is, of course, and international division.

SPT has a website (http://www.spt.subaru.com/microsites/spt/home.sptmain). It seems SPT tunes Subarus that come to the States...using products beyond STi. STi tunes all subarus, but mainly whatever it is running in the WRC. The research and development of those parts from STi reaches production at some point for Subaru aftermarket tuning.

I'm making this stuff up, but it sounds logical.

arondale