GMAC's idea of excess wear at lease end (
http://www.gmacfs.com click on "excess wear square" from left menu). "Any modification, including but not limited to suspension modifications, changing vehicle color or factory paint schemes, lettering or graphics, holes in froame, post-delivery customizing, engine adaptations, fuel system adaptations, tinted or engraved glass." That being said, someone still has to catch it, and since in many places GMAC (so probably other lease companies) use professional appraisers to inspect the cars at lease end, they very well could. Also keep in mind if you leave whatever on the car you spent all the money for just a short time. If you intend to change back, that could also effect things if not done properly. And if you should loose the car in an accident, you may not get time to remove your whatever. Its your car (life) do what makes you happy.