Good question. I have a bad answer. I'm not a body man, but if you think about it, the only way to correct your gap would be to twist the door, by the window frame to decrease gap, and obviously that can't be done, but it sure works good when installing aluminum storm doors. Wish I could help. My doors fit great along roofline, but they seem to be sitting a little low. I look at door fitment on every C2 I get a chance to look at, and I believe they are all different. I know i read, probably from an experienced person on this forum, that fit and finish on C2's is not generally very good. But it can be. With my car, I just love it so much, I,m learning to not be so critical, but then again, that,s basically impossible!