This is a group 5 racing car rear spoiler wing. I am actually getting this one made, and its ment to be build from 2 and 5 mm aluminium 6061 sheet. The wing itself is very simply made and is intended to keep real life production costs to a minimum.
The wing is made specifically for a BMW E21 and will fit the booth lid perfectly. However it can with little effort be made to fit any saloon car.