There are a number of things you can do right off the bat that doesn't involve a lot of money.
Remove the turbo discharge silencer.
Port and polish (aka sand smooth) the throttle body transition casting (on the inside)
Go to kmart and buy a $2 Blitz superfunnel, cut off the end and replace the airbox snorkel
Change your sparkplugs (yourself) every other oil change (about $15)
Upgrade your oil to synthetic Mobil 1
Use a fuel injector cleaner just before each oil change
Get a K&N airfilter panel
I am selling the last of my custom intakes. Look on my webpage to see how it looks. Your talking about a huge difference from stock. Turbosb, TweeksTurbos, and a couple others on here are using them, and they like the difference.