Can someone tell me before I yank these quarter windows out....I'm doing the vinyl top delete on 86 regal and I saw somewhere that I needed to get hard top windows to replace them, why is this?? WI'll the hard top windows go right in?? What if I use the old windows what's the difference? I wanted to avoid taking the windows out but the rust is behind one of the corners of the windows.... I know it sounds awful but we're patching the rust with fiberglass as we have no knowedge on how to weld. (We =my husband and i)