I have been stripping the entire passenger side bottom of the coupe to bare metal. But I am finding it extremely impossible to get all the old paint off. I am going to por-15 the whole underside. How important is it that I get every last inch of it to bare metal? And I don't mean that i am leaving big blotches just little bits and pieces that are in corners. For instance up near the front leaf spring bolt bracket, or in the very corner of the upper shock mount.