16 is pretty big for a Miata, so they're likely kind of heavy and could be slowing you down. Weight is a big concern with so little power. I'd go with a 15. If you're into stance, a 15x8 or as high as 15x10 (possibly with some fender pulling or flares) might work. Ideally, I'd like 15x8 with 205/50R15 as I've read…