normally I would say yes to this as it is known to trap water and moisture behind it, but in this case the car will only be driven in the nice weather and stored properly where I don't see moisture being a problem. Plus my car is a factory undercoated car and it has preserved it fairly well. The way I look at it is; I wont have rock chips in the wheel wells, it will always look clean and in the event that I do get some wear in it, I can always touch it up fairly easy.
