Hi Jasper, and welcome to BC!
Wow! Sorry that we missed this one for so long...
Yes, the NGK TR55s will work fine in your stock set up. Just use the .060 gap as set from the factory (double check to be sure).
The thermostat change to 180* Stant (brand) is a good idea, though I'm not sure how much mileage will benefit. The change will help keep the average temps down on your plastic upper intake manifold, which is a good thing.
The CAI mod is a good idea that will net you some increase, though I do not know of anyone here who has dynoed to verify how much. The rice pipe version is one of the better methods out there, though for your year, many consider the fender well intake (FWI) to be a better option.
There a number of ways to do the FWI and I suggest you do a search on it to satisfy yourself, but one method is to buy the kit complete from INTENSE performance.
Mike: 1997 SE w/ 183K, aka White Horse
, Gutted Airbox w/K&N, drilled 180* t-stat, tint all around, clear corners w/SilverStars, "PONTIAC" light up tail, PEMs, NGK TR55s