The spark plug wires have a 1K Ohm resistor in them in the end connector. Thus adding a plug with more resistance you are actually taking away spark. Also increasing chamber temps due to the hotter spark of the Platinum 4 plug. Some have no issues, others cars will not run smooth with them. But in the end you want a non-resistor plug for the older Merc's so you get as much spark as posssible.

__________________
~Jamie
_________________
2003 Pewter C230K SC C1, C4, C5, C7, heated seats, CD Changer, and 6 Speed. ContiExtremes on the C7's.

1986 190E 2.3 Black, Auto, Mods to come soon.....