Ive tried almost everything about spark plugs...
bosh, ngk, champion, beru, brisk and a few more I cant remember.
the thing: use the specific ones for your engine. Keep them in good shape.
Spark Plugs wont give you more power!!! thats a fact!!! changing old ones for new ones will give a better rev yes, but thats because the old ones were killing your bhp!!!
If you use N2O, High modified CR, Turboed a non-turbo engine or anything else that wild, then you should be aware of a new type of spark plugs.