A good running APU will map to 180-190bhp 200-210lbft. You would need a good quality DV and panel filter and to run super unleaded as cylinder temps get high due to the cat location and heat build up.
But IMO even before getting a remap carried out get the oil pick up pipe due, being a 99-T I Would say it's partially blocked (if it's not already bees changed) it's the oil pick up pipe which is the biggest issue wirh the APU engine after remapping, I have had many on the dyno where the oil light has come on.