There's a sensor or probe of some sort that will freak out if you simply block it off. Your best bet is to get an aftermarket tune that simply shuts off the EGR valve. Keep in mind, if you ever take the rig in for service where they may flash your ECU, you'll want to "revert" it back to stock before going in. Despite some folks around here having issues with this particular tuner, I run a SofaKing stage 1 tune and have been happy with it. I'm still only getting about 14mpg or so, but I have a lot of what people would consider "city driving" for my daily commute. Brand new intakes are cheap, and most importantly - spotless inside. While you're in there, you can pull all the swirl valves out so the wiring turns empty shafts and keeps the ECU happy. It also gives you a crack at the turbo coolant line that runs under the intake (I'm going to be replacing this soon).
The ultimate preservation for these Pasta-diesels is a full-delete and an Insane Diesel secondary oil filter system. This is still my end goal as well.
