From one state to another, there might be a difference, in one state any differences would be most troubling to me. One dealer or the other is breaking the law.
IMO, the answer would need to come in official form from your state's Department of Taxation and Finance.
I do know that in NY state, there is no such sales tax. It's a transfer, not a sale. The transfer itself is a service, not subject to tax, as far as I know. If it is, such tax must be included in the stated price because I've never paid any different amount.
Still happily answering to the call-sign Peetza.
The problem, as you so eloquently put it, is choice.
He is no fool who gives what he can not keep to gain what he can not lose.
-Jim Eliott, paraphrasing Philip Henry.