I did a LOT of research on this topic while preparing to convert to electronic ignition ('71 280SL).
Simply put:
* if your car burns oil at all: Bosch W8DC
* if not: Bosch W7DC
* if you want a REALY hot plug: Bosch W9DC
I replaced my W9DC with W8DC. Car runs great - but seemed to start better with the W9DC's.
I suggest Bosch because Beru products are just too hard to get, here in NJ, USA.
Here are my posts with supporting details:
http://index.php?topic=737,plug
http://index.php?topic=1472,plug
http://index.php?topic=1540,plug
BTW, here's a little scoop on the suggested anti-sieze material to use when installing plugs:
http://index.php?topic=1542,plug
--
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William Blair Wagner: blairwag@earthlink.net
Education is not always knowing the answer,
...but rather knowing where to look for it!
1971 280SL US Automatic
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