The OEM plug for an EJ201 is subaru part number 22401AA370, which is a subaru branded NGK PFR6B-11. You should be able to find the NGK part at any car parts store, or at least be able to order them from the internet.

Otherwise, if for some reason the NGK version is difficult to find where you are.. This plus was also used on the SVX, so here is a link to the appropriate options for an SVX on Rockauto: https://www.rockauto.com/en/catalog/...park+plug,7212

The coilpack is 22435AA020. I see several options to buy on eBay and Amazon for that part number. I do not know anything "performance coil packs", so perhaps someone else can chime in on that.