^^ I think you did fine. We bought our '15 TDI from VWNS and dealt with Tukk, who's a hardcore enthusiast and doesn't blow smoke up your a$$. At least that expensive tint is ceramic. When I bought my new R 2 weeks ago, the dealer also wanted $499 for the installed "lifetime" tint. Probably some run-of-the-mill film. I said I wouldn't pay more than $299 for it which is still about a 100% markup over what they would have paid. They quickly relented.
Regarding the doc fee - these fees are high almost everywhere nowadays, and in Arizona, by law, the dealer must charge the same fee on all transactions, which they LOVE because it gives them an excuse to say that they can't do anything about it. But in reality that's just BS because to the buyer, it's part of the bottom line price of the car, and the bottom line is ALWAYS negotiable, so the buyer should just take the fee into account when working his/her best deal. At such a massive discount up front, you probably weren't going to squeeze anything more out of them. At least they didn't try to stick you with a "desert protection package", or nitrogen in the tires - which Larry H Miller tried to gouge me for $279 for. What an insult to the customer's intelligence to even try to stick them with that nonsense.