Removing the impact bar from the door will, of course, remove all side impact protection but, it will also make the door really flimsy. If they're never opened, like on a dedicated race car, it'd be fine. Open it up though, and it'll probably sag and twist big time. Coupe's tend to get a twist in them, even when unmodified, simply due to the length and weight, and the fact there's no window frame to stiffen the door. Ever see F-bodies where the lower rear corner of the door sticks out and no amount of adjusting will get it to fit? Mine were like that. Cutting welds, a big diagonal ratchet strap to un-twist it, then reweld. So far, so good!