Looks like The Perrin Exhaust will be delivered tomorrow and Yes I plan on installing it myself.
(I have air tools and most specialty tools and a garage)
So far all I have done it an AEM short ram intake (makes a nice sound, but i think it actually hurts performancs [all the hot air]), and put some 5ziegen
17x7 RS6 wheels with Kumho 215 45 17 ASX's, and two fosgate HE2 12's and a pioneer mp3 deck. I also replaced the factory headlight bulbs with sylvania silverstar bulbs. When I bought it the all the windows were tinted except the fronts, and the undercarriage was sprayed with sound deadening material. And of course no WRX is complete without a good radar detector (beltronics 935 express).
Maybe someday Ill try this:
http://www.tmz.com/wrx/build3.htm
My plans for the future are to replace the downpipe (one with a high-flow cat in the mid-pipe) and the uppipe (I have heard that the 05 models up-pipe don't have the guts in their cat so I might not replace that). I also wan't a cobb access port, and some whiteline front and rear sway bars. I also have 2 pairs of Boston 6 1/2 speakers that Im going to try and install. Then I will be happy... I also want a really agressive set of studded tires for my factory rims for the winter.