Since your car was imported from Thailand it may well be a sump guard if its made of steel. Would not be cheap to buy from Mercedes-listed at nearly £300 from Inchcape. http://www.detali.ru/cat/oem_mb2.as...GM=717.444&CT=F&cat=515&SID=52&SGR=015&SGN=01 You could replace it with the lighter item 5 at about £63 if you wanted to "lose weight" Apart from preventing all manner of crud ending up in your engine compartment it plays a vital aerodynamic role in smoothing out the airflow under your car which is probably good for a least a couple of MPG at speed.
W210 E280 estate 1999 facelift; 6th gen honda accord coupe 2000
Just changed the oil on my W210 for the 1st time since I bought it earlier in the year. I was very impressed by the cast aluminium sump, which is much more substantial that any other sump I have ever seen.