ALTERNATOR SHOT

Does anyone know a quick way to replace a w201 2.6 alternator? suddenly, Sunday, lights began to come on, battery and brake light first, then after I had road service jump start it, only SRS and ABS lights stay aglow, which means I have neither, and am running 100% on the battery......and its 9 degrees outside. I heard its a half hour job, but it sure doesn't look like it, I see only 4 inches of wiggle room, and have decided it must come out from underneath. any tips greatly appreciated (including let someone else do it)..,........Rick