Here you'll find tuner kits that'll let you to reflash, reprogram or tune your cars ECU EEPROM chip (the brain that controls how your car runs). With these tools you can optimize performance and behaviour of things like: BHP, Torque, RPM, load, fuel injection, timing, transmission, etc.
* Which tuner kit should you get? Whichever supports your exact car model/year. So remember to check vehicle support list before buying.