I wanted to add my experience.
I made the changes and it has made a tremendous difference. I live and work in the center of the downtown of Chicago, IL (i.e., the Loop). In certain places, especially my office, I've had very bad call quality, which I would characterize as blocky, choppy, and digitized. I read this post, made a call to my friend, talked for 5 minutes, and noticed the same bad call quality. I then made the tweaks with a healthy dose of skepticism and called my friend back. Clear. Not perfect, but very very clear. As clear as my ex-Blackberry.
I'll keep my eye out for any changes to the battery.