I have a Sony XNV-770BT reciever in my vehicle with a very nice handsfree Bluetooth interface to my phone.

The only downside is the sound quality and sensitivity from the supplied cabin hands-free microphone. It appears to be a cheap omni dynamic mic and the noise cancelling is most likely in the reciever. It uses a standard 1/8" mini plug.

Any suggestions for a replacement?

This is it:

In any audio situation, you can't beat proximity when it comes to maximizing clarity. Here's what I use:

Etymotic Research, Inc. - ETY•COM™ Headset (http://www.etymotic.com/ephp/er22.aspx)

Works great.

When I was a pilot and flying Cessnas, it was a David Clark H-10/40. The mic was just a half inch from my lips.