It would be very interesting to hear how P1 works out on your car. It appears to have a number of claimed virtues. It is scratch polishable, and has no exposed edges to trap crud or lift; and peels off in one piece if needed. A number of OEM's have played with opaque single layer versions of P1 for in-transit protection, but the maths and process issues don't stack up for that type of situation even though the product has performance tested well. The number of layers (thus material thickness) might give a small colour shift. Probably not noticeable on the back wings, but you could always ask for a sample to be sprayed on a piece of glass as a pre check. I'd guess that it needs a booth environment for application in order to avoid small dirt particles being trapped in the dying film as they won't be removable later. Might be worth asking if they mask around the rear lights or remove them for spraying, just to avoid any surprise if you have to peel the P1 off at any time.