I recently swapped out my CD player with a newer one (that plays Mp3). My original unit had some problems so I had to swap it out anyway. After swapping out the CD player, the entire problem went away. The buzz and whining noise is gone. The bluetooth is also now crystal clear to the other side now; no more complaints about wind and road noise.
Apparently, my original CD player (late 2003 production) wasn't compatible with the new TCU.