I know im not wrong in sayin 7 is the cooler plug, this is the correct plug to run in a mapped lcr.
Agreed, 7 is definitely the cooler plug (in NGK anyway). Just wanted to get it clear that 6 is standard and 7 is the cooler option.
Wouldn't recommend 8 though, they're a bit too much in the LCR and can cause problems with day to day driving.