I'm getting ready to change the plugs on our C36 engine which use Bosch copper-core F8DC4's at just slightly under $2 each wholesale.
If I remember correctly, one issue of "THE STAR" stated that the newer 4-electrode Bosch platinum plugs (pn#4418 for the M104 engine) really are better and can be substituted for the Bosch copper-cores. Of course, this is a 200%+ premium over the F8DC4's.
Did I remember, read, or interpret this wrong?
BOSCH is backing this up with a 100% part refund that states:
"you will feel the improved performance in your vehicle when you use Bosch Platinum+4 spark plugs. If you do not experience smoother acceleration, improved fuel efficiency and optimal engine performance, return the plugs with your dated sales receipt and Bosch will refund the purchase price of the spark plugs."
The coupon can be found here:
1988 360TE AMG