Hey guys, what is the difference of the Indmar recommended Motocraft CYFS-12FP (597037-16 in manual) versus the Motocraft SP-526's? Are the heat ranges different or anything? Also what is with websites charging crazy amounts of money for the CYS-12FP plugs? I've seen anywhere from $250-600 lol. I go on Advance Auto website and they sell the CYFS-12FP plug for only $5.19 which it to $83 total. That's a fraction of the cost compared to boat-specific websites and stores.