That is a really most impressive job! Somehow the shape looks rather better in your pictures than in model pictures on the box art! Nice detailing work, though I can understand why you'd save your energies for the Heller kit. Good idea with carving off the sills as well... I'm going to have to do something similar. I'm slightly sad to hear that there's someone else out there on the hunt for a Heller coupe... I've been looking for months! If it's any help, I've confirmed that the same plastic is in the Airfix 1/24 E-Type Coupe box (in a lurid blue) and also in a Gunze Sangyo box (ie the GS coupe is NOT a derivative of their own convertible), so don't get suckered into buying a high-priced Gunze from Japan via eBay...
Still, SMW is just around the corner, with its Kit Swap and traders...
best regards,
Matt