port n polish job on the head, itbs, better exhaust, a lil weight reduction if you can, lighter flywheel, under drive pulleys, etc all the bolt ons that 1 can do.
in my opinion, n/a is all about freeing up rotating mass and power/weight ratio. and like any engine, air/fuel delivery, compression and timing. you make up for the lost power with throttle response and superior power curves in a light car.