just seen this video and i was wondering if this would be beneficial? is it as easy as this guy makes it out to be? what gaskets would i need to do this job? has anyone else done this mod?
sorry for all the questions. i was just curious.

YouTube - Grand Prix GTP Tear Down Explained/Port and Polish

Porting like that will help a fair amount. I've done a few and it is easy if you have the tools and know what your doing. After porting I was able to drop another pulley size and dropped a pound of boost stack. This just means the air was moving threw faster and not backing up. My suggestion if your going to do this is pick up another LIM and supercharger, port those and do a top swap when ready. I seem to remember it'* about $60 or so in gaskets to do the job. A set of LIM gaskets, a supercharger gasket, 2 O rings and a throttle body gasket. Takes 3 or 4 hours to finish the job.

ok sweet, how much hp you think it would gain?

You really wont gain anything from the porting it'* self. You will be able to flow more air without boost stack. If you drop 1 pulley size a rough estimate is about 10+ HP. A good porting with a good tune might get you 20 to 25. The porting is only one part of the solution, your next choke point will be the valve train.