There are many aftermarket ECM chips for the vehicle's computer that boost horsepower, torque or any other performance feature that you are seeking. Another option would be to modify the exhaust. You can get a muffler and wider pipes allowing the air to move out of the car more freely. Removing extra weight, although does not technically increase horsepower will improve acceleration performance. Many people who strip/street race will remove the spare tire, rear seats, carpeting, etc. or pretty much anything that is not necessary for the actual function of the car.

1. if you have an LS Integra (142 horsepower)the best way to really bump up your integra is to install the vtec gs-r engine with comes with 170 horsepower stock. do the usual mods to that engine (examples in number 2 ) and you have around 180 hp for about $4000. this is also the easiest. 2. if you already have the gsr and its engine then you could just do the usual mods such as intake, full aftermarket exhaust, ignition upgrade...that sort of stuff expect to spend around a grand and make around 15 hp. of course prices and hp vary based on different brands. this upgrade also goes for the LS engines mentioned above. 3. up you want to go what they call stage 2 upgrades then that involved new more aggresive cams with upgrades to the fuel and ignition system. this is of course in addtion to what is mentioned in number 2. 4. the first thing you really want to make sure of before you do any upgrade is make sure that you engine is in top condition in every way. otherwise it would be foolish to upgrade one part while the other part is weak. 5. what most people dont remember is that the best way to make you car faster is to make the driver faster...you. if you have a stick (if you really care at all about performance then you have will have a stick if available. if you can afford it take a driving class...it will award you more than any performance part (except maybe nitrous).