[GLH_TC 16V]

The problem with the platinum plugs is that the platinum retains the heat from combustion. This retained heat in the electrode can cause the engine to detonate (especially in turbo cars where the combustion chamber temps are higher). I don't see this as a problem with naturally aspirated cars, but turbo owners should beware. This goes back to the my turbo Dodge days where lots of people were having problems with the platinum, although I never had a problem with them myself.