I'm not positive (sure some of you audi/VW heads know better) but he's currently waiting on a company over in Germany to release their modified housings to hold Gt28r's or Gt30r's to mate into an S4 engine bay. I'm guessing the regular turbo is much to big to fit in there so they're coming out with something that should fit. He's expecting to break into 750-800 crankhp #'s w/ upgrading injectors, converting to a FMIC, and some head porting....