I agree with Benzfan, I have a '98 C280 and it has a "two cat" assembly. One of mine busted inside and was rattling like heck. I actually bought the complete two cat assembly on the internet for about $250.00 and had a local indie replace it. It installed like a champ (cost me $60.00 in labor) and it passes Texas smog testing just fine and runs well.

The guy is hosed.