yes you can use copper plugs or i suggest iridiums in the V6. honda uses the platinums so they can say 105K before your first tune-up, but unfortunetly platinums are not a perfomance plug as some manufacturers may lead you to believe, ie: bosch. if you had an I4 i would say NGK or denso coppers cause they are easy to replace every 1-2 yrs. since the back 3 plugs on the V6 are a PITA to change i would get iridiums since they will last longer and provide better performance than platinums. i suggest NGK iridiums since they are cheaper than denso and have a thicker tip which will last longer.