Buy a new car.
Nothing--chips, mini-superchargers, air cleaners--excetera offer noticeable-on-the-street extra power. Some of these will make the car SLOWER 0-60, but quicker in the quartermile. A super/turbocharger will reduce engine life. Nitrous will help for short spurts but will hurt engine life.
Something that will make a car faster is stickier tires. The Toyo TSI or Michelin Pilot Sport will make your car feel like it's gained 20 hp.
