The stock pulley for the '96-'99 is a 3.8. The usual swap is to a 3.4.
The best place to start before the pulley swap would be Cold Air Intake,then the exhaust.
Here'* a thread to get ya started in the right direction on the CAI
The exhaust would be a matter of preference, Most of us around here run a Magnaflow F-body hi-flow muffler.Make sure the muffler is a single in/dual out.
When changing the pulley,you have to run one range colder plugs,so now would be a good time to do a tune up. Autolite 104'* or NGK TR55'* are suggested,gapped at.055. O2 sensor,plug wires and assorted fliters.
A 3 jaw puller is not a good idea. A special puller is used to remove the pulley,since the puller is also used to press the pulley back on.
If this is going to be a one time swap,the puller can be rented from either Intense racing
Also,you'll need a 715 belt to make up the difference after the swap.
I got my pulley and rented the puller from zzp and believe me,it made a world of difference
Maybe one of the gearheads can chime in and add,if there is anything I missed.