If I were you, I'd have some porting done, a valve job (maybe bigger valves) maybe up the compression (I assume it's fairly low), and put a cam in it with new valvetrain. If you know a machinist you can probably have everything done for like $1,000-$1,500. Sounds like a lot but if you know someone you can maybe get it all done cheaper. Do the labor yourself, it's not so hard. That money will go WAY farther performance wise than buying a TB for a few hundred, CAI for a few hundred, etc...