I have 13 sho pp,manuel states to use sp-528 which gap at 0.30,after reading all articles here majority members favor the updated version sp 534,which I also orderd for future use,they have same part # on plugs as the sp-528 which cost more,and harder to find just box is diffent,also give LIVERNOIS A+++++ for recommending everyone to use a step colder plugs gapped 0.30,my original wew all at 0.35-0.37 and pretty cooked with 6,000 mi, on tune,lesson learned.
