I have a 1985 CA. The original "trap oxidizer" is dull cast-iron. The replacement (forgot name) has a shiny stainless cover. It is more like a catalytic converter (honeycomb ceramic). Rollguy here sells a "test pipe" which replaces it. If you still have the OE, M-B will still replace it for free, I understand.

The blue saucer is good and they continued that 1986+. I added one to my 1984. It is basically a vacuum amplifier for the VCV "signal" to the transmission, plus adds a few features for acceleration.

Your emissions controls likely no longer work and no new parts available. There is a diagram posted many times which shows what parts you can remove, which will clean up ~1/2 of the vacuum stuff in the bay. You can also remove the EGR valve with plates Rollguy sells (~$15). After that, plus rerouting the AC h.p. run, I can now loosen the alternator bolts in 5 min instead of an hour of cussing.

People fuss that the CA air filter is $45 if you can find one. I just stack 2 cheaper filters (Wix 46070), for 1985 Toyota MR2. Others have the air filter housing above the intake manifold on a bracket which shakes & breaks. I added the 1985 air filter to my 1984.

The electric fuel pump will work. However you provide it, the injection pump needs >10 psig at its inlet. I assume the lift pump is still bolted to the block, beside the IP. If the housing is OK, it should be easily rebuildable since the design is common to most Bosch lift pumps and kits are ~$15 (ebay). Indeed, I wondered about adapting another Bosch pump but most have the ports facing in ways that would bump into components in the engine bay. If yours still has the OE white plastic primer pump, lose that for the smaller & better black one (many posts, white one sucks in air).

To check boost, I just tee in a vacuum/boost gage to the tube off the intake and clip it under the windshield wiper to view as I drive, or when more motivated, ran a tube thru the rubber grommet into the cabin. You should see ~10 psig under hard pedal as the engine rpm increases. Don't goose it up or you risk melting pistons.

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1984 & 1985 CA 300D's
1964 & 65 Mopar's - Valiant, Dart, Newport
1996 & 2002 Chrysler minivans