Rep Power: 813

so i've had these plugs in my car for 3 yrs and nearly 30k miles. according to denso, since these IK20 are the ultra fine tipped racing plugs, they should be changed at 30k miles. i went ahead and followed that advice and swapped in a fresh set. the old plugs still looked great, nice brown color and zero electrode wear. i put in the new plugs and noticed no difference at all in how the car drives. that means the old plugs were working at their max right up until replacement time. overall i continue to recommend these as the best performance plug for our civics. made in japan by a quality manufacturer and currently has the smallest electrode size (better than ngk). you can usually find a set of 4 on ebay for $35-40 which over 3 yrs is worth every penny. not so much for the extra hp, but for a smooth engine and less strain on the electrical system (means ignition parts last longer and can provide the same ignition spark with less starting energy). possibly resulting in better gas mileage as well. i drive in all sorts of conditions (mountain, highway, hard and soft acceleration, and these plugs held up great).