I just realized that for the past 6 months or so I've been using NGK V-power plugs (BKR6E-11) with a copper core in my 94 GSR. Is this the wrong type of plug to be using? I was just on inlinefour.com and from the looks of it, they advised against using non-platinum plugs in DOHC vtec engines. Why is this? Am I doing anything detrimental to my engine by using these plugs? Thanks for any help and please let me know if you suggest any other plugs instead...