I believe the panel in question is officially called a "sound encapsulation panel." Looking at mine, it has suffered some damage over the years from steep driveways, but better the panel than the oil pan.
May I be so bold as to recommend to anyone tired of removing the panel for oil changes to consider getting a Topsider? MB has thoughtfully put the oil filter on top, so why complicate an otherwise straightforward oil change by doing the filter from above and the crankcase draining from below? MB has also designed every engine since the 1970's with topside oil drainage in mind . . .