Just tried a different phone (first one was HTC 8x and second is Nokia 920) and they both seemed to be about the same quality on my end in the car. My wife said that she was able to hear me just fine with the Nokia...but that was just one phone call.

The signal strength seems to be fine - no static or disconnects. Though I did notice with my HTC that if it took a while to connect, the sound would be particularly bad.

The sound quality of the speakers in the car is just kind of lousy. It sounds like the audio clips pretty heavily and there's not much "body" to the sound - it's very thin sounding so makes things hard to hear (especially female voices that are higher pitched to begin with).

I'll check the purple cable and see.

Has anyone upgraded any of their Bluetooth components?