OK, I understand how detonation is the enemy and can do serious harm to your engine, which is why the knock sensor will retard timing to guard against detonation.

So, lots of modders will put colder plugs in their cars to guard against knocking and the retarded timing.

My question is how do you know how many steps colder to go?

I see several folks with SRT-6s have gone two steps colder. Why two? Why not one? Why not three?

The reason I ask is because over in Mini Cooper land, they all seem to recommend one step colder, whereas here in Crossfire land they recommend two. That makes me wonder why.