Lyrics probably can be heard from the rear but I don't think this is the main purpose of the rear speakers. I believe these speakers mainly help create an ambience within the cabin. Although it seems like the main audio source remains in the front, the rear speakers make it possible to keep the sound levels balanced. It is a thankless job but without these speakers, the overall sound would probably not be so smooth. I have friends who are very picky when it comes to audio and they were rather impressed by the quality of the SLK sound system. So far, my only disappointment as far as sound is concerned is the automatic sound-level control. I think mine doesn't work.
