[Tatsfield]

If the tuning remap was written into the ECU, it is possible that any software update on that area of the ECU would overwrite it and you actually wouldn't have it any more. However if the rewrite is in a plug in unit and not actually in the ECU it might still be there. Generally, as far as I understand it, these pick-a-back tuning devices tend to be crude fuelling adjustments to the ECU output and not anywhere as effective or safe for the engine as professionally written ECU changes.

The OP sought advice on the comparison between a well known quality rewrite like Superchips and Volvo's own tuning shop Polestar rewrite. Both are good stuff but Polestar stays where it was put and other remaps get overwritten by ECU updates. That might be Volvo's way of protecting its market and they may go out of their way to erase unauthorised remaps to influence Volvo owners to buy Polestar. I did, so it obviously worked!