Tried the Diamond tweaks for Bluetooth. The carkit still does NOT work for the Altima 08 anyway. The audio becomes very clear and usable after switching the connection to handset and back to Hands-free. This is an indication that either the wrong profile is being selected or the wrong parameters are being used when the car first connects to the phone. The car works fine with other phones and WM5 phones. Microsoft/HTC broke it with WM6/WM6.1. Hoping some of the hacks will fix it as many of the carkits and some headsets have this issue!
See this link for more info:
http://forum.xda-developers.com/show....php?p=2669889