What brand/type of spark plugs do you guys suggest with a tubo kit? (specifically the STS kit @ 8 psi)

 

NGK TR6 gapped around .030 depending

 

I have checked on heat ranges and prices on the NGK plugs and have decided on one of two style of plugs and I was wondering which would be a better selection: the NGK TR6IX which is one heat range colder or the NGK BR7EF which is two ranges colder???