Price being no concern, what are the really best plugs to buy for an 89 420SEL ?? I know the W8 DCO is the top regular standard plug for this car, but is it better to use the Quad platinum plugs for the very best overall performance ?? Please advise .... getting plugs in the next day or so.
Thanks, BC

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Ben Harrison Carter
1999 Mercedes ML320 87K
1992 Mercedes 300CE 89K
1995 Corvette 29K -- Sold Dec 09
1989 Mercedes 420SEL 99K -- (Sold 4/08)
1968 Mercedes 230S (106K) (Sold 9/06))
1976 Mercedes 450SEL 130K (Just sold - 06)
1961 Mercedes 220Sb (sold years ago)