procharger

I just got a packet in the mail today from procharger. They are advertising their stage II intercooled supercharger for the v6. If i were to have this installed on my stang would the value of the car go down? I don't plan on keeping the car forever and im planning on trading it in or selling it in a few years. Their nearly 400 hp claim is really catching my eye but if im just going to screw myself in the end i dont see a point.

Thanks for your help,
-Ryan (rhynost)