No. And there is a mechanism that a purchaser may use to show what the true value of the used car is, and be taxed at that amount.
Are the opportunity costs of availing yourself of that mechanism higher than I think they should be? Yes.
Will people find a way around this law? Yes. Rather than pay $300 for a certificate of value, I expect that a lot of people will just pay some guy with a used car license $100 for a straw man transaction (which is taxed on the sale price, not book value), and then pay the real seller the balance of the sales price on the side. The buyer saves some taxes, and the used car dealer makes $100 for thirty seconds paperwork.
That just makes this new law a poorly thought out, and hurriedly slapped together, burden on the law abiding and an opportunity for crooks -- not unconstitutional. I get aggravated at people, DUMMIES or Freepers, who assume that any government action that they don't like must be illegal, and that they ought to sue.
As a Texan you ought to know that "a poorly thought out, and hurriedly slapped together, burden on the law abiding and an opportunity for crooks," describes a lot of what the Texas Legislature does when it meets for five months every two years (and yes, I know this particular bill was passed in a special session). The only defense I can offer for the Texas Legislature is that the Legislatures of States who allow them to meet year round, California, New York, do even worse.
I don't really understand the need for the $300 "certificate of value". A dealer estimate on the cost of repairs needed to get up to book value should be all that's needed to establish the value. I don't know of any dealership that charges $300 for a repair estimate. This is the part that sounds like a scam.
Any authority exercised but not given is unconstitutional. I have no right to set the value of something you want to buy. Only the seller has that right.
If an individual doesn't posses that right, the the political body of the People cannot posses that right, and there is no way they could have given that authority to the State.
My personal likes or dislikes never entered into it.
As for the rest of your post, I agree!
A guy sets up shop with a huge collection of damaged quarter-panels, mangled bumpers dented doors etc. for 35 bucks you can be buying a wreck.
Work around two (I really like this one, and will talk to our mayor about it tonight) a registration jurisdiction in Texas puts a licensed dealer on staff who appraises cars at their true market value for free. After word gets out people flock there from DFW metro to register their transactions, sucking money from DFW, and pumping the local county.
I see it as a great opportunity for somebody.