Note to self, do NOT move back to Illinois!!!!!

There are so many different levels/values a car can be built to, I'd hate to have someone just pick a number and tax me.

I'm assuming that a part of it has to do with getting a specialty (antique/Street rod) plate. What would happen if you just plated the car as a normal driver (say in the case of the Mustang)? It should be old enough to be emissions exempt, and as I recall Ill doesn’t require a safety inspection.