Hi, I know this post is a little old, so I'm not sure if you found your answer. But I'll go ahead and share my experience. I have a 2009 C300 and the Tune2Air is like magic. I believe most smart phones are able to connect to both the Tune2Air and your car's Bluetooth (tried on iPhone 6, iPhone 5C and Nokia Lumia Windows phone). It's basically like having your phone connected directly to the interface cable, giving you full steering wheel control functionality. It even pauses the music and switches back to your car's Bluetooth when you make/receive calls.
I did a TON of research on this and it's truly the best value for this purpose. If you want a seamless experience, there's no cheaper alternative that I could find.
I got mine on Amazon for $90.
Last edited by BenzHubby; Feb 25, 2015 at 10:34 AM.