A custom burned chip using data from several dyno runs would probably result in more power. It also could possibly smooth out any lumps or bumps in the street manners.
there is always hidden power since the stock computer is designed for low emissions and the best gas miliage possible. altering the fuel and timing curves to be more hp orriented will help even a stock motor but the more mods you have, the more of an effect the tune will have. if you have any plans for forced induction in the near future, get that first if not, get a chip if your "done" with your motor