sorry I didnt get back to you sooner work has me in Mexico. The EGR cooler delete is not that hard to do. I can give you some sights to go to, but you really need to do some reading to let the idea sink in real well. there are a few kits you can buy to delete the EGR cooler, if you dont want to make one your self. A few tips....get a real long 3/8 inch extension to get up to the uppipe where it conects to the turbo Y pipe. If you have two sets of hands it will help. to get to where you can remove the Intake manifold and remove the EGR cooler will take about 5-8 hours total. Then depending on how well you can fabricate a delete kit will depend on the total time to do the kit. Me and a buddy can do this from start to finish in about 4 hours, and that includes removing the Uppipe and cutting the EGR port scoop from the uppipe. I dont believe the 04's had that. I would pressure test the intake manifold before you reinstall to make sure you dont have any leaks.
some reading materialEGR delete thread
more reading on EGR
4 pages of EGR delete threads.....read
This isnt a hard mod to do, but I reccomend reading a lot so you are prepared for it. This is something everyone with a 6.0L should do. Dont listen to the BS people say about the 6.0L being a bad motor. Most of those people dont understand the first thing about diesels. I have a 02 duramax right now, and have owned 2 dmax's and cant wait to sell it to jump back into another 6.0L.