ATLparanormalOG
Member
FYI...after spending time with NTK tech support. the replacement for the 23506 and the 23099 is one new part number, the 23179. Not sure about others and did not ask since I drive a 97. The only problem is that the supply chain has not caught up as of yet. I got one directly from ngk.com yesterday for about 42 bucks plus shipping. THAT WAS THE LAST ONE, again verified through their distribution center. I think that I read somewhere that Summit is expecting some around November 6.