So I've been doing some reading and have a question or two on proper heat range for spark plugs. Everything I've read and heard about superchargers calls for a 1 to 2 step colder plug. How about in an N/A application? Trying to figure out proper plugs to run on a friend's car. I'm just trying to understand how the whole heat range thing works. My friend's car is all motor: close to 11:1 compression, port and polished head, cam, intake, header, exhaust, adjustable fuel pressure regulator, etc. We know it still needs further tiing and fuel enhancements, but what kind of difference in heat range (if any) plug should he be running? The engine's been eating plugs (stock) and just trying to make sure they are the right plugs before we write it off to the car needing the afore mentioned fuel/ignition upgrades. TIA!