Hey all, GET 3.5.1. Do whatever you have to do to get the dealership to honor the TSB. Just make sure to do a g-damn master reset first thing after installation (even if they said they did it). Testing it out after installation I thought "Meh, not much there, a little better I guess". I hate master resets but finally relented and did one a couple of nights ago (for reasons listed in my above post). Got done doing some work around the house and figured I'd go for a little drive because I wanted to test the call quality thing a little more. Told my wife to answer her cell when I called from the road (area doing 65mph and some road noise) to test cell-to-cell (I had called her post-install and she had just as tough a time hearing me as she did pre-install so I figured nothing was any different). Her first reaction was "Wow, what did you do? You sound a thousand times better". I could not hear any of the "wind tunnel" background whooshing noise I have always heard in the car since 3.0.2. I also told her not to answer the home phone as I wanted to leave a voicemail so I could hear the sound quality for myself. I did just that and it was great. Still a little hollow and some echo but that is the nature of hands-free. Totally understandable though and no background noise. I also had her send me a couple of test texts and receiving the texts and having the system read them back to me worked fine with an iPhone 5 and iOS6 (still can't send but I am going to continue to try and find a workaround for that). Hands-free calling now works as well, if not even better but it was a while ago so I can't be sure, for me as it did w/2.11.
This is a call quality freakin' NIGHT AND DAY DIFFERENCE. I am still kind of shocked and in disbelief. No wonder Ford put out a demonstration/delivery hold recall on lot cars and made the update mandatory on those. GET IT (and do the damn master reset after).
.......here's a lockpick. It might come in handy if you, the master of unlocking, take it with you.