A cracked catalyic converter there is nothing you can do but replace it, I believe it is welded on, you will have to have a shop replace it or find someone you know that is a very good welder.
The EGR valve you may be able to do something about, go to my website
http://home.comcast.net/~lj_robins/99suzuki/ and click on EMISSIONS then EGR VALVE, there is a procedure there on how to clean it out and how to test the electrical connector.
What trouble codes did the engine record?
