By line in do you mean an aux?
Even if not standard, one of these
MERCEDES AUDIO 20 AUX IN IPOD MP3 B CLASS C CLASS E CLASS ML SLK CLK 2M CABLE | eBay
is easily added!
Once that's in I connect a bluetooth module to it, and then connect from the iphone by bluetooth for playing music - once setup it connects automatically once I get into the car, and is completely wireless.
Even if not standard, one of these
MERCEDES AUDIO 20 AUX IN IPOD MP3 B CLASS C CLASS E CLASS ML SLK CLK 2M CABLE | eBay
is easily added!
Once that's in I connect a bluetooth module to it, and then connect from the iphone by bluetooth for playing music - once setup it connects automatically once I get into the car, and is completely wireless.