I just bought a 1999 mirage, 104,000 miles. So far I have Fixed the gas cap door, trunk latch, hood latch, wiper fluid reservoir, changed oil, removed oxidation from finish, waxed. Tires are good, brakes are good, suspension feels good. Transmission fluid looks normal and seems to shift at the right times

I have few concerns:

Car seems to hesitate at times or just a bit sluggish, not sure if its the transmission or what. I admit that I haven't driven a car for a while with this small of an engine(1.5 Liter) Is this normal? It seems a lot better on the highway than city driving.

The plugs/wires look newer, should I just change them anyway?

Anything that I should do to this car?? I dont have any maintenance logs
to go by

Thanks