I don't know if you have ever felt the ABS kick in, but if you haven't , you should try it. Find a relatively empty mall type parking lot close to home (in case ya break something). With a long safe clear stretch ahead of you, get the car up to 20-25mph and then stomp on the brakes-hard as you can-like a child kid ran out in front of you. If your brakes are working properly, your car should stop very quickly and in a straight line. You will hear a growl fromthe ABS. That's just it doing its job. If the car does not stop straight, but fights to go off to one side, it might indicate a stuck piston in a brake caliper (pulls left = stuck caliper on right). If it does not seem to stop as quick as you would like or if you don't hear a growl, you could have a problem with the ABS unit or the computer that controls it. If the car seems to stop straight and quick, well that's just worn front shocks. If all goes well and it feels like you dropped the anchor, well that's the MB magic at work.
Oh, and lest you worry about the abuse to the car, this is a standard part of the defensive driving course the MB club runs for members before driving events.
My wife's '88 560SL does real well in this test. It is comforting to know she can stop quickly if needed.
BobK