in my experience of working on cars, including 7 years professionally as a shop owner and lead dyno tuner, NGK's always gave the most consistent results. This was true with every brand of motor and ignition system I worked with, from domestic to import, standard OEM set ups all the way to capacitive discharge coil on plug with multiple ignition amplifiers. Race cars generating upwards of 1000hp right on down to a 180k mile CRX HF pushing 53hp to the wheels.

I've also tried Autolite, Bosch, Denso, and motorcraft among many others, probably every brand you've heard of. I've never been in a single situation where a NGK plug was outperformed by another brand.

Sorry for the post length, but I felt I had to justify my position which is one of experience.