You might want to consider having stronger valvesprings installed at the same time, though I believe some people run the GT1 on stock springs. If you get new springs, I can't remember for sure if you would need different valvespring retainers or not. Someone else will be able to tell you for sure, or you could ask ZZP when you're ready to order your cam.
Chances are you will want a different PCM program to complement your cam, but it isn't vital. The car will still run on the stock PCM, but you will probably be running lean in all RPM ranges. Also, you might need a few of your trouble codes tweaked. The GT1 is not known for setting a "random multiple misfires" code, but I think it happens in a few cases.
All in all, you have to invest a bit of money to get a cammed car to run at its full potential. You can't just have the cam installed and expect it to run perfectly. There are issues that need to be massaged in order to develop full power.
1997 SE w/SLE package
"White curse? I think it'* more like.... WHITE FURY!" - MyLittleBlackBird