Definitely bring another set of eyes. Yours will be distracted no doubt with the deal and vehicle operations overview.

Do not let the CA let your new truck idle for an hour or two while going over the iDrive and setting up your cellphone.

Bring your iPod to hook up if you got that option or a CD burnt special for your ride home.

Get your window sticker.

Plan ahead which email your going to register with the BMW assist feature. I wonder if there is any advantage to a gmail address due to the google maps feature?

Camera.

Enjoy!