I too bought a D4 and from almost the start I noticed odd audio issues when the volume of my voice went above mid range. However, I didn't want to swap to a CLNR so I hoped it would get better. It didn't. It got so bad I couldn't stand to talk without the call being on speaker phone. Verizon sent me out a CLNR D4 and out of the box it had audio issues. I was sent another that wouldn't turn on. They sent me another, and this one had the battery and adhesive cover hanging out of it, the empty cavity full of dirt and some hair. I took a picture and called them saying I wasn't going to get tagged by Moto for $500. (I was told from the start if it looked like the battery had been removed my warranty would be voided) The tech I spoke to then said my only replacement options were the D Razr (NOT MAXX), Samsung Stratosphere and an older HTC phone. When I asked if I could get a MAXX I was told there was a new policy in effect that they will only be sending out Maxx CLNRs for those with a Maxx.
I am HIGHLY disappointed in Moto right now, as I really loved my D4 but I couldn't deal with the bad phones anymore. Now I'll have to find a way to live without my keyboard.