Would it be a big deal or look bad to mix model A coupe parts? I have seen the difference between 28-29 coupe bodies and 30-31 bodies but how about 30-31 cowl and doors and 28-29 rear quarts to make a sport coupe?
IMO it would look bad to mix the 2 styles. As you know the 28-9's body lines are rather flat whereas the 30-31 are rounder and have a bead along the bottom of the body. Plus, depending upon what 30-31 doors you use (sedan vs coupe), your overall body length could be off (if it matters). If you already have the parts, sell off the 30-31 cowl/doors and buy some 28-9's.
i think you can run the earlier fenders on the late or vise versa. at least i hope so i love the shape of the early fenders and im looking at a 30 tudor.