Aluminum heads and spark plugs

Just looking for a nicer fit and finish and if it improves efficiency, so be it. I've gathered all the pieces for my engine build and am just throwing around ideas.
Got it. Keep it in your head as a passing idea and don’t think about it again. There isn’t much of anything to be gained at the spark plug if you can’t change its location. Make sure the tune up is clean and the ignition system is as good as it can be and you’ll be 99.99% of the way there. Everything else you might gain is minimal and should be left to the 1%ers like pro stock, NASCAR, top fuel. Let them worry about stuff like that.