So I'll bump this thread with an update to my car.

I had a local exhaust shop make a new system for my car. I had a Thrush welded muffler installed, with no resinator. 350s do not have a cat. This replaced something I had put on in a time crunch... a cheepie muffler from Auzone that restricted to probably 1 1/4" inside.

Thrush 17656 Welded Muffler on a Mercedes 350SDL Turbo Diesel - YouTube

Overall I'm thrilled. It's not loud, yet audible. If you listen close you can hear the turbo

You should have seen all the soot that blew out of the tailpipe the first time I took off I'm going to cut the crappy muffler apart and see how loaded up it is inside.

-J

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1991 350SDL. 230,000 miles (new motor @ 150,000). Blown head gasket

Tesla Model 3. 205,000 miles. Been to 48 states!
Past: A fleet of VW TDIs.... including a V10,a Dieselgate Passat, and 2 ECOdiesels.
2014 Cadillac ELR
2013 Fiat 500E.