great inputs guys, but i am having a code p1354 which says "misfire during start cyl 7" which prompted me to think of changing my spark plugs since i couldn't find any info concerning this code. So i removed the spark plug and i noticed it was a NGK spark plug stamped BMW with the same part # BKR6EQUP made in japan with a code K92R written in smaller letters. Right now i'm thinking whether the regular NGK BKR6EQUP form the regular part store will work. I'm not sure if that BMW stamp is for it to sell for $21.00 or is there really a difference in performance considering the mileage form 50K to 100K. So for i'm still not sure what brought in that code. Also the plugs i took out was form my 03 4.6 and they still look good and clean. Tell me what you guys think!!