Few things I'd like to comment on here....
First... I wouldn't suggest DP Tuner for a few reasons. First, I don't trust their tunes, I've seen a few motors open up with their tuning. Second, you pay for the chip, per tune and per reburn which is just silly now a days.
I would suggest you go with a TS based chip like some have said here. I had a Tony Wildman chip in my 95 and loved it. Mudman, FYI, you can't stack tuners. Adding a ts chip to your truck with the Edge programming on there will do nothing. The TS will override the programming of the Edge and the only gain you will see is the difference between crappy Edge tuning and much better Custom tunes from whomever on your TS chip.
First things before any tuner comes into play should be air intake, exhaust and gauges... At the very least, an EGT gauge to keep an eye on your engine temps. You can run 1200* all day but over 1250* for extended periods of time is not recommended.
Talk to the tuner you plan to buy from, call them up and talk about the options, most can tune out the overboost code anymore so no need for a boost fooler or boost annihilator. (All a boost fooler does is regulate what the PCM sees for boost numbers to a number set below 23-24psi where it then throws an overboost code. It doesn't change the boost that you are actually making.)
Some tuners I would call are TW, Swamps diesel, Beans Diesel, Gearhead Automotive...
Also, don't buy a chip for fuel economy... You will be disappointed. Fuel economy is dependent on your truck being mechanically sound, no lift and big tires, maintenance is key, and your driving style.
Hopefully that helps a little bit. I'm on my 4th 7.3 so I guess I have a thing for them.....