1999 2.3l
It Depends on what you want to do to the car. I have completely redone my car. Suspension,Radiator, Pulleys, Brakes, Seats, Stereo, Bushings, Exhaust, Rims, Reprogrammed the ECU. I need to get it Dyno'd but it probably now has 200hp to the rear wheels with the AT. The car is alot of fun to drive.
If you want a bit more power I would look at trying to find a 3.0. The car is plenty spirited as a 2.3/2.5l but you have more options with the 2.8 or the 3.0 for modifications.
This is a great place to find info and discuss what you want to do with the car.