Galaxy Note 2 here, had minor stuttering issues with the stock rom in the beginning, i deleted the pairing and tried again and haven't had that issue since. Switched to an AOKP based rom and that has been flawless.
They probably gave you a crappy estimate until they run your credit. Kinda odd they seemed so adamant about the 2.9%. I would say check out some other dealerships. The first dealership I went to refused to even run a credit check until I agreed to buy the car and sign the paperwork. I walked...
I'm sure if you wait awhile the oem antennas will start popping up online. The other option is to ask your local autorepair shop to order you the oem part.
The first few times for me gave me the license expired warning, just keep trying and it will go away. After the first day I never saw error message again. No way of doing it from the steering wheel but its pretty easy to mash on the volume control for mute. Congrats on the car!!
Thread exists here regarding the tech package http://www.mazdas247.com/forum/showthread.php?123834564-Did-anyone-get-the-1600-GT-Technology-package-option&p=6231565#post6231565