Clare Snyder wrote:

Modifications that go against federal motor vehicle safety standards
ARE illegal - whether it is enforced, selectively enforced, or not
enforced doesn't change that.

Well yeahbut, but, but, ....
https://www.youtube.com/watch?v=oncY6GKwjt8
https://www.youtube.com/watch?v=4FlBc-0QvSU
https://www.youtube.com/watch?v=GI71up9UPmM