Scott, Standard tunes, no intake mods,only code it has ever thrown was vehicle overspeed (OOPS!,LOL). I downloaded the new updates from H&S yesterday. The lie'o'meter is showin 14.5 which is a little better than it has been. We'll see when I run this tank of fuel through it.
P.S. Have you had anyone have trouble with EGT sensor? My gauge on the mini-max goes stupid when I'm on the gas,then seems to work fine when cruising down the road.:humm:

What tune do you all use to get the best fuel mileage? I also have a 2008 6.4, H&S Minimax, downpipe back DPF & Cat delete 4" SS exhaust.

Man, I cannot tell but about 2-3 tenths difference between any of them. I get 12-13 short run/working,and 15-17 hwy.:argh::dang:

Yes, I got 15 going to Michigan (350 mi) & get almost that on short trips, I tried all the tunes I had loaded & watched the lie o meter, it didn't seem to make much difference on any of them, running close to the speed limit with the cruise on. I was hoping for better mpg but it's great to have the power if needed.

i did the full delete this saturday morning and put on 500 miles with four sleds and three buddies in tow. ran the mild tune from h&s and rolling 75 got 18mpg on comp and 15.8 by hand, wasnt nice to it at all with it being the first run on the tunner.

however last monday the egr valve failed and the passageways for air flow were nearly clogged, just throwing it out there havnt dealt much with 6.4s yet.