Dinan Performance Engine Chips unleash more power by re-programming the fuel mixture and ignition timing parameters of the engine management system. Furthermore, the software safely raises the rev-limit (most applications), giving your BMW a broader power band and greater road speed potential in each gear. Significant gains are also achieved at part throttle, making extra power available where you spend the bulk of the time driving. AVAILABILITY: Please consult the general application guide below to determine if Dinan offers a specific chip for your combination of vehicle, Bosch ECU, and chip number. If you are not sure what your stock ECU and chip number are, consult the Dinan ECU/TCU chip identification guide under tech resources to assist in accurately determining that information so the correct chip can be purchased. HOW TO PURCHASE: To purchase, call the support staff at 1-800-341-5480 with the correct corresponding Dinan part number (see chart below) and they can assist in placing the custom order. Chips are build (burned) to order and not returnable.