yeah....no doubt about the budget thing. If i were you i would hit the Dsm forums and scrounge for knowledge. All the guys there will tell you that you are an idiot to go turbo with a gs and will yell at you for not have getting the gs-t or gs-x in the first place because it has a completely different engine. There is only one company that i know of that makes a turbo for the gs because most people start out with a gs-t in the first place if they are looking to tune it. You may recall the green car in the fast and furiouse. That was a gs-t, Mitsubishis holy grail (lol). A good mitsu forum is DSMTALK.com. You will learn a lot there. GL whichever way you go.
Ben