Check this out! They have the non-resistor type you need, shipping may be high though.

http://www.amazon.com/Bosch-F8DPP332-Spark-Plug/dp/B000CF3YQK/ref=sr_1_204/103-8760077-4156629?ie=UTF8&s=automotive&qid=1200679240&sr=1-204


Good luck

R in Bosh spark plugs # means resistor.

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1996 E320 since 1/16/08, 171K miles as of Feb 2011

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1989 300CE - R.I.P. Dec 29 2007
Other MBs (sold): 1992 300E-24 - 1979 350SLC - 1984 230E - 1990 300CE