factory cams are high performane,huge job changing cams and for the amount of work the difference will not be great,I know someone who tried and was a major headache and disappointing finish,he regretted doing it.
2 or 3 cans of V energy drink and it gives you a good driving buzz crank up the music and cruise they are great if you are feeling tired on a long trip as well much more effective than coffee.
spark plugs are often overlooked as a main ingredient of performance,people add cams and lifters,turbos etc, with out a thought for the spark plug and end up spending a fortune trying to get the performance to kick in.