welp Glad too be here, first off. second, the dimwit at autozone/napa.......one of the two,Gave me 4164 sparkplugs for my 1988 k-100lt. The google seach has them as 4164. Lining them up with the ngk's that were in there when I bought the bike, the thread/electrode depth on the autolite are 1/64th longer than the ngk. Trouble is most places have no listing for the bike.....being an '88. Should I replace with the 4163's or go iridium bosch? Which bosch plug would that be btw. Thanks in advance