Thought I would add this link here just as a point of interest. The link and pic below illustrate what a resistor plug looks like inside. (I wouldn't suggest the conversion!). That little cylinder is the resistor.

Resistor spark plug converted into a non-resistor spark plug (with pictures)



The interesting thing, is that the original Mercedes plug wire ends looked very similar inside. (I cut one apart once). The resistance embedded was about 5kohm. Bosch/NGK resistor plugs are about that resistance too.

Using new style 1kohm Bosch wires without the 5kohm resistor end but with a 5kohm resistor plugs would, it seems to me, be very much the same as using non-resistor plugs with the OE wires that have the 5kohm embedded resistor.

OE wires are, I am told, now almost unobtanium except from Classic Centre at a price!

This is what our OE wires used to look like:

__________________
Graham
85 300D,72 350SL, 98 E320, Outback 2.5