DO NOT change the gap on the Denso Irridiums. Will become very fragile under extream heat.

Personaly I have the ITV-22, no point going for the 24's unless your running well over 280bhp.

ITV-20's are just stock basically, may as well spend the cash on ford performance plugs.

Anything really from 212bhp, you should have colder plugs, or eventually you'll get the usual missfire.