Whats the Best spark plugs for the n/a

[raffa_mk]

I want to know whats the best spark plug to buy and which heat range for my ep91 n/a

i have a few mods, glanza inlet mani, corolla exhaust mani, and coming in a few days 200 cell cat with a straight through cat back system 2.5" with 4" back box

also have new plug leads fitted and will be replacing dizzy cap and rotory arm,

whats the heat range that n/a run on? am i right in thinking its 6heat range i am looking for?

raffa