Question about GPS Units with Bluetooth

I'm considering buying a Garmin Nuvi GPS unit with bluetooth. I have the BMW Assist with Bluetooth option on my car, which means that when my bluetooth phone rings, the system automatically turns down the volume of my stereo and rings the phone thru my stereo speakers.

Does anyone know if bluetooth GPS units will work the same way? Will the system fade out my stereo and play the GPS audible instructions thru the stereo speakers in place of the stereo music??

thanks!

The Nuvi has an option to connect to the FM unit...BUT you must tune to a specific set of stations, and not listen to music, just the voice commands. I used it just once....sound quality was bad.

Otherwise the Garmin Nuvi is a GREAT unit.

BTW, if you are ONLY going to use it in your BMW that already uses bluetooth, you can save a few $ if you don't get bluetooth in your GPS. I travel a lot so it is nice to have bluetooth in a rental car.

Bill

Also, make sure that the GPS bluetooth works with your phone... check the website.