The iridium spark plug provides a quantifiably better spark according to NGK, but I can’t give you numbers for increased performance. NGK is the industry standard for spark plugs. All models come with a solid non-removeable top EXCEPT the CR9E. Use the existing screw top off your OEM plugs with the CR9E. These plugs will fit the following models:
NOTE1: Don’t forget that if you have a DS1000/DS1100 motor, ST3, or DVT Motor, you need 4 plugs.
NOTE2: NGK often lists MAR10A-J and MAR9A-J for the same engines. The difference between the spark plugs is the 10A-J burns hotter
DCPR8E or DCPR8EIX – 907ie, 750-1000 Sport/SS, 620-1000 Monster, MH900e, ST2, Gran Canyon, Multistrada 620, 1000, 1100, Hyper 796/1100
DCPR9E – ST4/ST4S, 748, 916, 996
CR9EB – ST3, 998, 749, 999
MAR10A-J – 848, 1098, 1198, 4V Streetfighters, D16RR, Monster S4R, S4RS
MAR9A-J – MTS1200, 4 Valve Hypermotard and Hyperstrada, Diavel, Panigales, M821, M1200, SS939