Sounds like an IQ test. I paid $400 for my 1984 300D and sure wouldn't pay $920 for a pair of UCA's. There is minimal force on the UCA, mostly from the anti-sway bar in turns, so I can't see anybody's cast aluminum failing, and unlikely they differ much in quality. Depending on price, I might keep the aluminum and just change the rubber. I did that when the anti-sway rubber bushings degraded, causing rattles in my 1985.

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