Get rid of the DPF and the EGR. Go to cumminsforum.com and do a search on DPF delete and EGR delete. You will find pics of what the inside of the engine looks like with egr and it will make you want to take it off. Some people have gained as much as 6 to 8 mpg by doing both deletes. It does however void your warranty. To me it would be well worth it. It will make the turbo last a lot longer as well. The turbos on these trucks are having to be cleaned pretty often to keep them from sticking. They are vgt turbos like the 6.0 powerstroke and 06 and newer duramax's have so they have a lot of extra moving parts to get clogged up from the egr.