Could this be true? I've always been told that a tune, assuming they go deep into the ECU forensics, will be traceable. If it is traceable, how about this scenario? You use this tune, but when the FP tune finally comes out you switch to that. Would they be able to discern that there was a tune on top of a tune, or would they just see the latest?
The dealer will find evidence of the tune. You will have to pay to play on this application. There are many ecoboost engines that were denied warranty due to tunes from the various manufacturers. Roush would be the exception.