[CivicSpoon]

Depends on what kind of gains you're looking for. There are a ton of options available. If you're only looking for a little hp gain and some pep to the motor than basic bolt-ons are good (intake, header, and exhaust). If you're looking for more than just a little bit, then you can do a motor swap (Integra LS, GS-R, Type R). Of you could do a turbo kit, though with that many miles on your motor, you might want to think about rebuilding it or getting one with less mileage on it. But if you're going to keep the motor either way, it'd be a good idea to do maintenance to it (plugs, plug wires, maybe water and oil pumps, compression check, maybe seafoam it, t-belt, valve adjustment, check the cap and rotor, oil change, etc).