stevebfl, I just pulled the floorboard panel and found the boxes you described. The location seems to be a little different however. When looking directly at the panel there are three boxes, 2 silver and one black.

The 2 silver boxes are marked "Bosch" and each have one connector. One silver box is larger than the other and the larger of the two is situated towards the center of the panel.

The black box is labeled "Mercedes-Benz" and is the largest of the trio. It has 2 connectors and is situated to the extreme upper left of the panel. Is the alarm box, or could my car have not had an alarm?

It does not look like anything has been removed from the panel as the entire panel appears to have no extra holes or unconnected wiring harnesses.

Thanks, and I look forward to your reponse.