My '91 300E came with a one piece exhaust system from the cat back. The OEM replacement is a two piece outfit. I paid $412 for it from Caliber motors. Don't remember if that price included shipping.
They had a heck of a time getting the old muffler off the cat. Had to use an impact chisel to do it.
The original exhaust system was just fine except that the weld to the resonator rusted (from salt) and I failed to have it fixed before it was too late.