I can tell you. I’ve done it. Same exact problem with the resonator rusting. I just had a muffler shop replace the rsonator with a straight pipe.
It sounds fine. Only slightly louder. No drone

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Current fleet
2006 E320 CDI
1992 300D - 5speed manual swapped

former members
1984 300D "Blues Mobile"

1978 300CD "El Toro"