I came from the world of the Turbo`ed euro cars. The thinking that had dyno proven results was go with copper core plugs and replace them often. turbo motors are hard on plugs. The added airpressure in the combustion chamber actually acts as an insulator hence why you have run narrower gaps on and Forced Induction motor. Some people call it blowing out the spark but in fact it is when the gap is to big and the resistance of the surrounding atmosphere prevent the spark from jumping.
With all that being said I ran regular Autolite 3947 plugs in my 1.8t GTI. Stock it was cranking out 135 at the wheels. After a few upgrades and I was pushing an honest 210+ at the wheels running pump gas. All on $.99 plugs. I changed them religiously at 10k miles and never had a problem with them. I did have a coil pack problem but that is a typical 1.8t problem they still cant figure out 10 years later. I used to run split fire plugs in my 65 mustang now i run autolites and change them at 30k. Since it isn`t FI I don`t see a lot of electrode or annode corrosion but for 8 bucks it`s cheap insurance my 45 year old car will run decently