Correct, your car is utilizing the OBD-II computer. You can't chip it. I has to be reprogrammed. Sharking will give you some added power, but not as much as a chip on an OBDI computer. You will gain about 10-15hp and 10-15lbs of tq. And it will smooth out the power band, raise your redline and remove the top speed governor.
Pulleys would be a great thing, new performance cams if you want to spend the money. Why don't you want to change the intake though?
Hell anyway, the most effective way to gain HP with the intake anyway is to debaffle (refer to FAQ/DIY section) and simply drop in a K&N or Green filter...It will add about 4 or 5 hp and inprove throttle response.
Another thing, improved performance software is designed to work best with intake and exhaust upgrades. So if you have all of that taken care off, you would be getting the best results.
5 Speed Manual
Alpine CDA-7895 Head Unit
12" Alpine Type-R, sealed box
Pioneer 400w amp for $20 at a yard sale (to replace my fried MRV-1507)
Infinity Kappa 4" 2-way speakers(rear)
Infinity Kappa 5.25" component speakers(front)
Debaffled airbox, K&N filter
Tracked Mud on carpets
Shampooed and cleaned carpets