spark plugs and spark plug wires ?

No spark plug wires are needed with coil-on-plug WRX's. I don't know if the older JDM models had wires or not, but something like the NGK silicon spark plug wires would be your best bet if that's the case.

The best performance you can get out a plug is the simple NGK copper spark plugs. It's the most conductive material that can handle combustion chamber temperatures. The downside is that they wear down faster than other materials, so you have to change them often. Iridium plugs and the like will give you more performance averaged out over a much longer life span in-between changes. But as with most DOHC boxer engines in a Subaru engine bay, you probably want to go for longevity. :)

He's right about this being a pain in the ***. I would stick with NGK OEM plugs and there are no plug wires so nothing to change there. We have electronic coil packs so if those go then you just have to buy new ones but I have never seen aftermarket ones for these cars. For the spark plugs, I would only change to colder iridium plugs if you upgrade everything including the turbo and push over 18lbs of boost.

NGK 4 Prong Spark Plugs and NGK Hot Wires are the best from my experience for most Import applications

have fun changing those plugs. its a pain on my sti