All modern precious metal electrode spark plugs have copper core conductors--break any one of them open and you will see. Also there is no such thing as a "copper tip" plug, a copper electrode would melt and not last 30 seconds. Most all non-precious metal (platinum/iridium/etc) plugs use a nickel/chrome alloy (very rarely tungsten) for the center electrode. Here is a good article about spark plugs
, it was edited by yours truly for WeaponX so it has a bit of sales pitch to it, however the technical information is accurate.
As to what to use, I run Champions in everything we own, they have been making spark plugs for 120 years and if there were better ways to make them they would have figured it out or bought the technology. Their single platinum plug is all our cars need as unlike the EDIS dual coil setup on the earlier 4.6L Mustangs the COPs all fire with conventional polarity...
- 2003 GT, UPR X, FRPP 24lb/h, Magnaflow, PP 70mm TB & plenum, Delta Force tuned,
Steeda UDPs, Ralco flywheel, RAM HDX clutch, 3.73s, 262 rwHP/305 lb-ft.
New ride (7/1/2013) 1998 Mercedes SL500-5.0L 32V VVT 326/347 HP/tq