Hi Chris,
i am sure your cad model is great. But I could'nt resist the challenge, to do my own one. I converted it into STL format, which should work fine with printing. The scaling is not correct by now, but you might use it with your fantastic funny car built.
Cube https://www.dropbox.com/s/9rzwvkgvvvdnb19/Breather.stl