For the 1988 260E
the ubiquitous online catalog used by Fastlane, Rusty, Auto part autority, etc the listed catalytic convertors is by Miller (no photos). The CA (50 state) one sells for about double the 49 state version. Is the main cat different on the CA model or is it the insides of the precats that are different?

Unfortunately have not found any hints besides price as to the difference. If the CA precats are not doing much for emmissions maybe replacing with a straight pipe would be OK. If so i'd take my chances with a muffler shop and have them cut out the precat and Mig in replacement straight pipe. If I had a high enough lift I'd probably try it with my 110V Mig wire welder. Existing pipes look good (no significant rust) and weldable, but of course i'm only looking at the outside.

The rattling noise is a bit disconcerting especially during idle) but my main concerns are:
1. More back pressure? It's not plugged but maybe there is a reduction performance and increase in gas consumption.
2. Damage the engine. I have been told by a friend who is a MB tech that during hard decel the engine can actually pull back debris from the exhaust; that would be real bad.
3. Damage the main cat with debris. maybe thats already happened and should just ignore the whole thing until smog time.

Thanks for your input

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1972 450SL
1982 300D Turbo