I am a new owner , have a 2000 in silver - 145k , very nice shape, all documents since new. It had " A " - plugs at a Honda dealer in Auburn, Wa at around 60k, so I decided to replace them. Did not know anything about the " A " / " B " / " C " - or indexing , so got the first attempt at O Reillys. Then discovered the ABCs of these and got a set of " A " plugs because that what Honda had installed prior to my ownership. I was 2 plugs into the swap and noticed the head is stamped " B "... Honda did an incorrect installation... My question is - should I just get the B plugs sooner than later and swap them finally for 100% correct? Any idea how much diff it makes? The car had a irritating stutter when I first got it, I cleaned the egr plate and the hole from the valve, which helped a lot, but it still has a tiny stutter. Not sure what else the stutter could be ... Thank you all ... 