my set up:
- OEM bluetooth set up for phone calls. (not cheap)
- AUX cable and Kinovo BTC455 for audio streaming (very cheap)
and you have a few other options which people will chime in with.
2005 BMW 330i ZHP 6MT. Built 11-19-04. Bought 4-2012.
Stock: Nav, leather, PDC, Xenon
Added by me: OEM Alarm, OEM heated seats, OEM aux kit, OEM Bluetooth, intravee, M3 strut brace, BMW Performance Intake, Nappa leather arm rest, updated LCM (triple blink, euro hazards, trifecta lighting, 3 stage brakes), temp gauge