With the SPS you can have 3 performance modes. As I understand it when the Revo software is installed all 3 performance modes are flashed into the ECU and the SPS is then used to switch between them. You can also fine tune it yourself putting in your own boost, timing and fuel settings using the Select Plus software. A fairly typical set up would be a 98/99 RON map as default, a 95 RON map as the second performance mode and perhaps a race fuel map or a valet mode as number 3. Valet mode basically limits the revs to prevent boy racers abusing your car if you have to leave it at an airport for example. Then there is the 'stock' map plus an anti theft mode. I'm getting mine done next week and bought the SPS at Edition 38 today as they had a special show offer on. All Revo dealers have a £100 off until the 16th Sept, so if you are planning to get it done now is a good time. Can't wait for mine to be done