Bosch Super 4 HR78 R6 Plugs ok for 300E?
 

I've got a set of Bosch Super 4 HR78 R6 spark plugs. Not sure if these would be a good match for a M103 engine. Opinions welcomed.

http://aa.bosch.de/advastaboschaa/ki...&attrv_id=1024

Since Bosch has gone with Resistor plugs, most are switching to NGK with great results..
BP5EFS is a good NGK non-resistor choice for a high milage 103..

The 4's will work , but they are Resistor...........

Don't use the 4 prong plugs. They have too much shrouding of the flame kernel and the car will idle badly. I had those thinking that if 1 is good, 4 is better. The spark only still fires from one prong, and the other 3 just stands in the way.

OK, got hold of a set of H9DCO's from Phil at Peachparts. Pulled the HR78's this weekend, and my first impression is that idling seemed to be smoother, but haven't driven the car much since. Next week will be driving around and get a better feel of the H9's performance.