Car Newbie - Need Help - BIMMR 525xi - Bluetooth Music

Question type: Car Customization

I am the new owner of a 2006 bmw 525xi, and I'll be honest, i don't know a lot about
cars.  Wish I did.  I'm hoping here i can gain some knowledge and help.

What I'm wondering, is, because there is this HUD/navigation/display screen,
controlled by a little wheel beneath the shifter, to choose the option of
cd/am/fm/heating etc, am I able to replace that with a CD changer?  I suppose if I did,
assuming it were possible, that would render the control wheel beneath the shifter
useless, wouldn't it? Anybody, confirm/deny?
    I do know I have the option of being able to install a 5 or 6 disk CD changer in the
back - could I put a CD changer with bluetooth(BT)/USB there?  If not, is there such a
thing as a disk changer that has bluetooth as well?  I guess I'm going to try and
answer that question, assuming not, because that's directly connected to the CD
player? Anybody confirm/correct?
    The only reason I am asking, is because, I have bluetooth in the car for phone
calls, but I really want bluetooth for music as well.  From the research I've been able to
do and understand, as the car sits, I cannot listen to BT via the phone-call BT, and the
car would need some type of audio/music BT installation.  But, if possible, I'd like to
avoid the cost of the dealer installing bluetooth audio - could I do this by getting a CD
changer with a USB and bluetooth and have that installed somehow? But, as I said
before, with the dial and the display, I'm not sure that's a possibility in this model car.

tl;dr - Is having bluetooth installed via the dealer /local shop and installing software so
it pops up on the HUD screen the only way I can have the option of listening to music
via bluetooth?  Or, can I just go to best buy and have geek squad install a disk
changer, or, is that not an option with this model of car?  

Please beemer community, provide me with some helpful answers/advice?