The song you are inquiring about is the third spot mentioned in this article. Hope this helps.
Three new ads from Mercedes-Benz hope to show the "enduring relationship" between the company and its customers. Two ads focus on photographs of the owners posing with their cars while the third ad shows the loyality between owner and vehicle.
"Multiple Portraits" features the song "Au Reve" by DJ Cassius and closes with the tag line "No one ever poses with their toaster."
"Framed Portraits" is set to an acoustic guitar with a female crooning "Your picture is on my wall" and ends with the tag line "The Love Never Fades." The song is called "Amazed" (performed by Mozella) and was created specifically for the ad.
The third and most dramatic ad, entitled "Faithful," showcases owners as their various accomplishments are mentioned on screen. A powerful orchestral tune is heard during the ad and was created by Martin Hewer with the production agency Amber Music for the ad. (All info via the Adtunes.com Forums.)