Another F250 question

So after towing for close to 7 hours total this weekend and watching the diesel fuel running out of my exhaust I'm starting to consider putting a chip on and new exhaust in the hopes of bumping up my MPG. As of now I'm getting anywhere from 8.3 to 9 which makes for a very expensive weekend. The question I have is this; how much will this really help and is it worth it to void my warranty? I had several issues early on with the truck and ford stepped up and produced me with a 200,000 mile warranty. Obviously if I got bolt on exhaust and a chip that didn't leave an "Imprint" would be ideal but realistically how much can I improve my MPG? BTW its an 09 F 250 with the 6.4 and 43,000 miles on it. Thanks in advance
Chris

I have an 08 F250. Only got around 10mpg around town before tuning. Now I get around 16 city and 20+ hwy. Spartan is the way to go. Spartan Diesel Technologies. Give them a call or call Rudy's Diesel Performance. I think the web site is DPF-Delete.com or something like that. Rudy's is awesome costomer service and will answer any questions you may have. Spartan has great costomer service as well.

Marc is right, Spartan is the way to go. Just towed my 22' boat 600 miles over the weekend and got roughly 12-14mpg. I did bump my tune down to the Spartan 150 DFP off tune because anything over that seems to burn through gas while towing like its going out of style.
Spartan is rumored to leave no imprint but I have not tested it. Putting it on and off would be a pain in the ass in my opinion but if you had a serious issue that needed dealer attention it would be worth it. Have been running mine for over a year and have not had a reason to take it off. Do all my oil and fuel filter service on my own at home.

Are those mpg readings correct? I knew 07 was the last year for diesel engines before mpg robbing emission control but that is terrible. I tow with a 05 Savana 3500 with a 6L and 373 rear end. I get 15 not towing and 10 towing 08 210 SANTE. I cant see paying the extra for a diesel with getting that kind of mileage unless you are towing something huge.

Yes the readings are correct. It is pretty bad. I found a place somewhat close to me that can do a basic tuner and DPF delete kit but the issue is I would have to install the new DPF delete and remount the sensors. Thanks again for all the help