This is a pre-owned ECU from a manual transmission 3rd generation 2.0L non-MSP Mazda Protege. These are typically used when running a piggyback computer on a Mazdaspeed Protege. This ECU is plug and play, and will not throw any check engine lights when installed to your Mazdaspeed Protege. The advantage of running this ECU on an MSP with a piggyback spark and fuel controller is the fact that it has a much more linear base map which has a leaner air:fuel ratio and a more predictable timing map. This allows you to add fuel in a straightforward manner with an additional injector setup, and allows you to make more straightforward timing modifications with the piggyback computer.