The 6.4 is notorius for poor fuel economy.  I did have a 7.3 and 6.0 and the aftermarket programers did help a little but not enough to ever recover the cost of installing the programers and new exhaust.  so I'm with Wyndancer here, You may gain 1-2 mpg, But you will never save enough to recoup.  So if you add the programer, It.s because you want the horsepower gains, not the fuel mileage.

On a different note. I bought one of the new 6.7L engines.  Towing the same trailers, I'm seeing about a 1 mpg increase over my 6.0L fuel mileage while towing.  But empty I'm seeing 2-3 mpg better around town and 5 mpg better on long highway drives where I'm empty.  If you are going to spend some money, I suggest you purchase a 2011 truck with the 6.7L.  I realize you may be coming from a different truck use than myself.  I buy a new truck every 4-5 years  because I put a lot of miles on  mine.

Sorry I am late, but here goes.  The best thing that could ever happen to your truck is to rid of the extra EPA mess ASAP!

The Ford takes a little longer to reinstall the DPF mess to have service work done or inspections done (if needed) that my Dodge does but it makes these trucks run much better, much cooler exhaust temps and better fuel economy!  We did a 09 F-250 a few weeks back with an H&S Programmer and delete kit and set the programmer on the 60hp setting and has NO smoke at all.  With this kit you just unplug the egr and the programmer turns if off and there is NO CHECK ENGINE LIGHT problems.  Also the Ford do NOT get loud like most people think, if the muffler is removed it has a little deeper sound than factory but nothing more.  Ford has a much better tranny for these upgrades than any of the other trucks right now.  We found a good all around setting for towing and fuel economy is the 60hp setting.  But on my Dodge I have did some testing and found that the 120hp setting does best for me on fuel economy if I am just driving and not doing any towing.

On the Dodges like mine this kit with no muffler makes them sound like the older 5.9 engines and the only time I get any smoke out of mine is if I use the 120hp or 175hp settings.  But until someone offers aftermarket parts for the Dodge C/C trannys I have to leave mine set on the 60hp setting to save the tranny while towing.

On my Dodge it takes me and 1 other person about 40 mins. to return it back to stock with no signs of ever being changed.  All of the aftermarkte kits are all bolt on parts for the exhaust so there is no cutting or need to removed factory hangers.  The Ford is a litlte longer because they have more bolts holding everything on.  Dodge has 4 on the DPF and Ford has like 8 or so.

Another test we did was the new testing on diesels (that the EPA has started out West) and my truck passes the snap (smoke) test but will not pass the visual test until I reinstall the DPF and plug in the egr.

We have not checked the fuel mileage on the Ford we adjusted but it does run like a different truck now.  I know on my Dodge driving empty 80 miles a day with 20 of them being intown and with the cruise set on 70 while on the hwy I have been getting 18mpg.

There is a couple of companies that are good with Fords, you can go to www.powerstroke.org and there is a section just for this year models and they have tons of info.  Spartan and H&S both have a great product and a good price for a mild tune and DPF delete kit.

All I know is the egr is part of what pulling spent gases back into the engine.

When I bought my truck I was changing the oil every 3-k miles or so because is was nasty as soon as I changed it.  Since I have done this delete kit I have extended my service to 7500 miles and still have petty clean oil.  So I am not only getting better fuel mileage I am saving money on oil changes.

The first 20-k miles the oil was changed 6 times @ $65.00 a time that is $390.00

Since the kit being installed at 20-k miles and extending the service to 7500 miles I have had the oil changed (this week makes) 5 times @ $65.00 at the total cost of $325.00.  My truck has 57-k on it now so I have gone 37-k miles for $325. in oil changes compaired to 20-k miles for $325. in oil changes.  If my math is right I cut my cost well over half in just oil changes.

Most people just look at the price they pay up front and try to figure out if a couple of miles per gallon will justify the cost.  The way I look at it is who cares about the cost "is it going to make my truck run better and or last longer".  I can not figure out why anyone would want to put the spent exhaust gases back into the enigne to re-run it again