Okay here is the thread for STi plugs: https://www.i-club.com/forums/engine-power-ej25t-sti-2006-wrx-90/what-spark-plugs-buy-44475/

Has anyone actually changed their plugs yet?

 

yup... I use the NGK 6097 BKR7E :banana:

 

Yep!

 

I use denso iridiums 1 stage colder for higher boost. I also have a set of denso's from my 02 WRX w/ about 2K miles on them if you need plugs. It only has a little miles because I went to a colder stage on my 02 WRX as well.

LaR

 

I found some at Napa in Waipahu. Not all napa's carry them, but I got 8, for just over $2 each. They have 80 more at their warehouse.