A few months ago, we replaced the head unit in our car with a Kenwood KVT-516. One problem that we have been having is that the in call volume is too low for phone calls. We would need to turn up the volume to hear the caller. Unfortunately, this would affect the volume of music, which would be pretty loud at the end of the call.
It looks like the latest firmware update solves this problem. Now the KVT-516 has separate volume settings for hands-free calls, and other audio sources.