1. The documentation fee is BS
There are only three real costs when it comes to documenting the purchase of your vehicle: the cost of a few sheets of paper, the ink used to print the contract on those sheets, and the labor involved in handing you a pen, so that you can sign off on everything. That's it. Everything else? It's covered under the state mandated cost of tax, tag, and title registration.
2. Beware botched paperwork
This one really ticks me off. The amounts on the paperwork are perfect to the penny, and yet, they aren't the amounts earlier agreed on by you or the dealership. Your response should be simple: if a dealer does this, walk and never look back.