Forget the electric superchargers. They do not put out enough volume or boost to do any good. In fact they restrict air flow and can cause a loss of HP in mid to upper RPM ranges.

Ditto cold air intakes. They do produce some gain at wide open throttle, but little difference otherwise.

ECU re-flash seems to be the best bet, but mostly that is a HP vs RPM change.

If it were me, I would replace the air filter with a clean one, be sure I've got 0-40 oil in it and just enjoy the car.