Colder stepped spark plugs, which one for me?

[Eric BMW]

I was wasting my day away today and decided that I feel like blowing a couple bucks on spark plugs. I want to understand better which spark plugs I should go with. I think i'm set on NGK V Power's.

My real question is how many steps colder do I want or need. Do i want, 1, 2, or 3 steps colder? What's ideal for me. I'm making 300rwhp/305rwtq. Turbocharged, Stock compression @ 7 psi.

3 heat ranges colder: R5671A-9
2 heat ranges colder: R5671A-8
1 heat range colder: R5671A-7

[328iJunkie]

BRK6E NGK's are the normal ones. I wouldnt think youd need to go more than one range colder if that.

[eurrofreak]

One step colder or stay stock, you don't need anymore.