Originally Posted by mikey1600

So guys, sorry to ask again, how about that HKS part number for Spark plugs?

spoke to my local dealer today about the standard GTR plugs, they want $48/plug, this is COST price as I do IT work for them, I even saw it on their systems with my own eyes, retail was like $63+. fairly sure the HKS kits were around $200ish?!

so from here - HKS USA M-Series Super Fire Racing Spark Plugs

I've found - 50003-M40HL NISSAN 370Z 2009-2010 8(heat range) 1(qty) $26.97
also - 50003-M45HL NISSAN 370Z 2009-2010 9(heat range) 1(qty) $26.97

Which ones are everyone using, I'm GUESSING the 8, but want to be 100% sure.