Actually $53 is a VERY good price for a deal oil change! Mine charges $85 + the last time I checked, which was why I bought a Topsider.
The franchise quick lube places don't stock my filter size so I always had to bring my own, when I used to frequent them. Then I heard too many horror stories about overfilling crankcases, or forgetting to fill crankcases. The latter is a real nasty situation. If they start your car without oil and let it run a bit before they realize their mistake, it can cause very serious damage to bearings and probably other surfaces, but they won't show up for many miles so you won't know immediately.
Pay the $53 at the dealer and feel good about it (or find an independent MB mechanic).