Initially, he was in the passenger side while I showed him the noise. Then he drove it, and that's when he claimed it was the seat. I've known him for 3 years, cause he worked on the M3. He's a great mechanic, but for some reason, he just wasn't getting it that day.

To clarify on voice command, the 620 option may be software, or may be hardware. The option for Office, cover flow, text messages, etc. is definitely hardware.