The stud spacing on mine is 5-7/8" and they are 1/4"-20 NC SAE threads.
The opening distance from the top edge of the decklid to the bottom edge of the spoiler is 1-1/4". To the top edge of the spoiler at the same point is 1-1/2".
It is mounted as far forward as it can go and the outer edges taper to match the widening angle of the rear deck lid.
Mine is also painted black on the bottom .