BPR7EIX OR BPR8EIX
Which is better plus for running straight 112 octane???

 

Neither - you want to use copper. Also, octane doesn't determine the plug you want to use. It depends on boost levels and power level. 7s are stock range - if they don't work, then move to 8s.

 

You decide on the heat range of the plug as you increase horse power.
The more power you have, the cooler plug you want to run.

Don't worry about the fuel. You don't need to change heat range on the plug to use it.

I would recommend 110 octane.
112 is a bit much and you have to have a good tune for your car to make power with it.

 

i would run a "8" heat range over a "7".

i run a "9" equivalent, Denso IW27 to maximize what i can on california's crappy 91 octane. I also have about 10k miles on these plugs too.

if you go copper, i suggest a br8es, ~$1.75 ea from kragen/autozone or sparkplugs.com