I did build it, down to the window boxes. It is 8' x 12'-8" outside. My manual says the car is 11'-5 1/4" long, bumper to bumper. I actually omitted the framing at the lower back end to gain 3 1/2" and so I could add a bustle if I needed it, but the car just fits with the front bumper on. The doors provide a couple more inches.
The single door in front was to provide space to swing the drivers door open, but I needn't have worried- these cars are small!
In my locale I needed to submit a sketch for site plan approval- just a formality. I don't recall an inspection.
It was a fun project compared to home additions, etc. Of course the step ladder kicked out and and I fell and severed my achilles tendon, but I need to save that for another forum...
I tend to use my wife to excuse my own excesses. She's really not to blame. I think that we are all lucky that way.
Michael