Honestly I would suggest that you do it your self as well. The Down tube, Up-Pipe, and header are all pretty straight forward you really can't mess it up.. The hardest part of their install is removing and reinstalling the Up-Pipe. As for the inlet, depending on the type one doesn't always have to remove the inlet to install one.. Personally I was not real happy with the Perrin inlet. It was a little bit of a PITA to put it in, however it was doable with minor mechanical knowledge..
02 WRX.. "It's fun when it runs.. Problem is that it hardly ever does..."