Overview:
The Basics
http://www.ngksparkplugs.com/techinfo/s ... =31000&cou ntry=US
Heat Ranges
http://www.ngksparkplugs.com/techinfo/s ... av=31000&c ountry=US
http://www.ngksparkplugs.com/techinfo/s ... av=31000&c ountry=US
http://www.ngksparkplugs.com/techinfo/s ... av=31000&c ountry=US
Tuning
http://www.ngksparkplugs.com/techinfo/s ... av=31000&c ountry=US
Other FAQ ( Like the meaning of the codes)
http://www.ngksparkplugs.com/techinfo/s ... v=31200&co untry=US