i spoke with a gentleman from a Cat manufacturer called DEC Catalytic Converter. He said that the precats do have platinum in them and do help reduce emmissions. The ones MB sells and manufactures have precats that help emmissions and are the same for both 49 and 50 state applications. The 49 state aftermarket ones typically have all the catalyzing material in the main cat and no precat catalyzing. Although the main cat could bring emmissions low enough to meet the CA regs, CA does not accept emmission redesigns. Even if an aftermarket emmissions device with a unique design is as good or superior to OE CA only allows OE design solutions for emmissions.

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1972 450SL
1982 300D Turbo