This looks different from the Livernois' tuner device which re-flashes the tune. This looks to connect by wiring into the system similar to what I had in my old '14 Mini Cooper S. If that is what it is, it means you're not re-flashing the factory tune; this device modifies a limited number of factory parameters in the factory tune. When you physically remove the device you're back to the factory tune. So it should be absolutely hidden from the dealer as they claim. You might want to call them and confirm that's how it works. The downside is that these devices are not as effective or efficient as a re-flash. I had some querky issues at times with the similar device on my Mini Cooper. I would prefer the Livernois tuner over this, even though it's more expensive. Or even better, a dyno tune (even though it wouldn't be dealer friendly). JMO.