I admire how radical your custom is.
I'm confident it will be a great car when you're finished. I'd like to make a suggestion on the paint. If you paint the air inlets black and hold the edge to where the window would have been. You'll be able to hold onto the classic 911 look.
Here's some bad photoshop of what I'm talking about. I'm sure you have it painted in your head already. Just a suggestion.
Good luck.
Tom