DENSO spark plugs for the SUZUKI GSXR750 1988-1991 SLINGSHOT

DENSO spark plugs. These are X27E TR or U31ETR with dual ground electrodes. Made in Japan/China. He wants us to use the standard Denso Y27FER-C plugs in the front 2 cylinders and the Denso Y31FER-C in the rears due to them running hotter.