A cold air intake and performance exhaust would improve performance and are not too expensive either. You could also remap the engine to get some additional power.

 

Lower it and get some nice wheels, maybe a lip kit and some tint.

 

you can debadge your car for free, but leave the "H" emblem on there. i think this mod makes the car look very sleek and clean-looking (my accord came debadged, stock,from the dealer).

 

I'd go with a cat-back system first. It'll help you rev up quicker by replacing the Pixie Stix straw that you have for a mid-pipe. A good friend had a Vibrant mid-pipe on a custom axle-back system that performed great (although a bit loud for my taste due to the axle-back system that he had made). You should do some research and listen to sound clips to see what you want, but the mid-pipe on Honda's 4-bangers is a killer!

Another cheap upgrade are the pulleys. A lot of people say that they don't do anything and that you shouldn't remove the torsion damper. My friend & I both have autos, so that may be why, but neither my accord nor his civic had torsion dampers on them. Also, I have an amp and I used to have a sub-amp as well and haven't had any problems with the accessories being underdriven. BUT, the airflow has to be improved to allow quick revs for you to notice a gain caused by the reduction of inertial loads.