Dunno. You do know about the BD version?
You need to say whether you want the top to operate, that may/will make a difference.
When these first came out that was my first thought/question. On looking it over, I though the best solution would be to build a proper half-cage, then gut the folding mechanism and replace it with a frame to which the panels could be attached, turning the car into a fixed roof coupe. I don't know anyone who has done that, most of the racers seem to pick the softtop and put a hardtop on it.
Safety with weight saving FTW!