What are the best proven plugs I should get for my engine? Im assuming stock...what are the stock one's? I have an 03 CL type S 6-speed I/H/E/P/3.7 IM/ Ridgeline IM Spacer

 

NGK Iridium IX ZFR6FIX-11

 

The factory installed OEM spark plugs were NGK: PZFR5F-11, gap @ .039-.043"
DENSO: PKJ16CR-L11 was a secondary recommended replacement to the NGK.

This was the old school technology of over 10 years ago, so for a few bucks more go with the newer NGK "Iridiums" as TheMightyQuinn had previously suggested. They come already pre-gapped, just be careful handling the tip and put a small amount of anti-seize on the threads before installing.....don't get any on or close to the tip.

 

By the way, that part number is for the Type S models, the premium models use ZFR5FIX-11.