The items mentioned above are typical of "bolt-on" performance parts. To get you above the crowd you would need machine work on the heads and block including:

1) porting and polish the intake and exhaust ports
2) deck/shave the heads
3) overbore the cylinders

I prefer n/a power over forced induction as well. I'll be looking for a high mileage (read: cheap) donor, so a rebuild of the engine will be in its future. While the engine is apart is the right time to perform the upgrades noted above.