Nothing at all wrong with Herculiner on the bottom of a driver!!!! On our '49 Mercs we use it on the inside of the fenders to keep from star cracking the 'glass... BTW, same thing will be going on the insides of the fenders on the '36 Plymouth in the garage now. On a show car that does most of it's travelling in a trailer paint is great, but where durability on a driver is needed, bed liner works great...Quiets down the road noise a bunch, too...