exhaust system

Hello everyone. I am pulling the motor out of my 86 300E and I noticed inside the "mini cat looking cans" that are bolted to the exhaust manifolds are almost completely clogged with carbon. Is that what they are........."pre-catalytic converters" before the exhaust gases flow to the catalytic converter? It seems to me that if they were causing increased back pressure, this is what could have caused the engine to grenade. The number 2 piston was completely gone. When I removed the head............nothing but a wrist pin/connecting rod staring back at me. Is there some way to salvage these or should I just buy a whole new pipe with converter. Who and where is the best price for this? Thanks!

Frank951, '86 300E