Hi, I have an early 2005 car and the standard spark plug is NGK PFR6Q but from 2007 the plug changed to NGK PZFR6Q-11 , the manual chart says these are suitable for the earlier engine when fitted as a set, I'm just wondering if anyone actually knows if these plugs have any real advantages over the early ones. They do project 3mm or so further into the combustion space and have a bigger gap so possibly a better placed and bigger spark? They do unfortunately also have a 50% price increase over the early plugs as well so just wondering if anyone has any experience and if the price increase is worth it.
Regards Chris.