Not only is this a great way to get every ounce of power out of your 4g63 with a stand alone ECU (such as Autronic or AEM), but it will also improve spool time, driveabilty, and last but not least, gas mileage. For an additional $69.99 you can tune for 2 types of fuel. This way you will have settings dialed in for pump gas and another setting for race gas. Price does not include extra labor and/or trouble shooting. Price is for tune only. ECU installation is not included. We are also a VP Racing Fuel dealer and can provide fuel for tuning and purchasing. Please inform us if you are going to need fuel in advance.