What Will said.
As for the tax, yes, you'll have to pay when you register the bike in Louisiana. You can minimize the hurt to your wallet by convincing the seller to write the sale at a much lower price than the actual selling price. The state will use that bill of sale for the tax basis.
"The one thing that unites all human beings, regardless of
age, gender, religion, economic status or ethnic background, is that, deep down inside, we ALL believe that we are above average drivers."