All of the controllers listed above are known as piggybacks. These are units that get spliced in to the factory ECU harness and are basically signal modifiers. Normally these systems can only add, remove or delay voltage signals from an engine sensor to your cars ECU.

The Greddy e-Manage and the AEM FIC are slightly more advanced than the other units and can be tuned via a laptop. The Turbo XS D-Tec is unique in the fact that it is programmed via a Nintendo Gameboy Advanced, yes really!