My friend has a plugged cat but doesn't have the money to spend on a new one right now. Any ideas on how to fix it or help it right now? It's a 2001 grand prix. I heard somthing about drilling holes. Thanks a lot.

 

How have you determined that the cat is plugged? If you unbolt the down pipe from the rear exhaust manifold and the car runs well, then you have a plugged cat.

As far as how to fix it... Well, buy a universal high flow cat (magnaflow or catco) and bolt it in! Should be able to do that in your driveway for $50-70 depending on where you get the universal cat from. You just have to measure the pipe. If your friends Grand Prix has the 3.8L, then I believe it is a 2.25" in-out cat, but measure it first just to be sure. If it has the 3.1L, then it's probably 2" in-out.

*EDIT* The MagnaFlow universal cat is $64 on SummitRacing.com
The Walker universal cat is $54 at Advanced Auto
Direct fit MagnaFlow is $179 at Advanced Auto

If you wanted to truely do it in your drive way without modification to the stock exhaust, I'd get the direct fit and some new bolts.