BOLT on wheel spaces are not necessarily illegal. If they do not affect the track of the car they can be used. That is if you use them to enable the use of different offset wheels for example. I had 25mm bolt on spaces on the back of my car as I had changed the struts at the front and had to use different offset wheels. The rear track remained the same and the car ws engineered with these in place.
I have 2 available as I have since installed a 60mm wider diff - I paid $135 ea for them to be made. I believe that the Adelaide 'drift wrecker' does bolt on wheel spacers for drift cars.