To me, no B pillar and no window frames= hardtop. Be it 2 or 4 door, as noted by Mark. Coupes are a little harder to define. The XA hardtop/ coupe could be accurately described as either. Ditto the 2 dr Monaro. The blue Buick is a billed as a 2 dr sedan by Buick. I would call that a coupe, as it meets my criteria for one. Keep the same dimensions, roof line and over all profile, then delete the B pillar and window frames and you get my Buick 2dr hardtop. Or "2 Dr Sports Coupe" in factory speak. Nothing sporty about it!