Mikel89us is correct.
Manufacturers don't "de-tune" engines.
They DO set them up for best MPG which may be contrary to your desires of wanting more power.
But without modification of the engines ability to "burn more fuel" per minute there is no "tuning" that will add any power.
Popular upgrade is an electric fan for the rad, replacing the belt driven fan, this will free up some horse power and also increase MPG, small changes but not 0.
Cold air intakes(CAI) are a waste of money, stock system IS a CAI
Exhaust changes can move the power band lower, they don't add power, they allow the power to be used starting at a lower RPM, stock system exhaust is tuned for mid-range power band.
So if power band is 2,000-3,000rpm now it can be lowered to 1,500-2,500rpm, thats an example not "the power band" for Lima engines, lol