What range of plug should I use?

[Spoolin18]

The car came with bosch platin plugs. I upped the boost to 14-15 psi, didn't rewire the fuel pump yet, Still got the stock exhaust, cat and all, no intake or special filter. Should I go with the ngk 6's or the ngk 7's. I'm doing the rewire, opening the exhaust. I'll probably turn down the boost to 14. Its been at 15 for now. Open the intake with a filter. or maybe 2g maf. with ecmlink.The tip and electrode broke off on the bosch, but it looks like they're old.

 

[GRAVEDIGGER]

I would say go with the 7's

 

[hereitcomes]

The tip and electrode broke off?? Where did they go!!?

NGK's are a nice upgrade. Look into some 8mm wires to update the rest of the spark