You just need the retro fit BT loom ask at your local dealer, for the e46 coupe its
Bluetooth Wiring Harness, BMW p/n 61-12-0-143-309 = approx £120.00 (could/will be different for the cab).
BTW, Uk cars came with the MFSW but NOT phone prep as standard.
53, M3, Silver Grey. Reto-fits: Modded Mk4 DVD, OEM Bluetooth, VR Control, Rainbow/Alpine Speakers, Sony SOT Amp, HK Sub, CCFL, Intravee II, NightMode.