For Bluetooth your best bet is probably to install a Denison Gateway 500 for ~ $400. This will give you iPod, AUX, bluetooth, USB and more for less money than the OEM bluetooth unit.
If you want NAV it will cost $1,600 to $3K. You can try these guys located in Quebec
to see if they can do an X3. If not then the CIC retrofit guru is Patrys
. Send him a PM or email.