If you stack a properly tuned SCT with the timing set up right for max power and safe cylinder pressures... your asking for nothing but trouble.
Here is the problem.... An SCT tuner can give you any timing he wants. He can give you any duration, pulse width, injection advance/retard... anything. But he knows that there are limits. If a little is good, and a lot is better.... than is a sheit-ton better? No.
Do you like streatched head bolts, blown head gaskets, pistons that were smited by overfueling and out of whack timing that would void any warranty on any day of the week? If so, stack away!
Many tuners will toss big timing in to make big power.... but like most things, there are limits. Take a 140-160HP Xtreme or Looney tune and stack some other jokers module on there and you took great power and reasonable safety... and tossed it out the window. You may make a few more HP in the short term.... but at what cost?
As to the Edge Evolution, it is an OBD2 digital gauge and a downloader/tuner. So, if you return the truck to OEM stock program with the Evolution, your using the OBD2 gauge side only. Call it an Edge Insight at this point. You use your SCT for the tunes, and the Edge as the gauge.
I dont know what you have from Banks, but lets assume its a module that has a wire harness under the hood that plugs into various sensors. If this is true, you have a module. A module and a tuner can in theory "Stack", but again, understand that when Eric or DJ are creating tunes, they are pushing you "As Far As Reasonably Achievable" without the dooms day of death hovering over your engine. Take this tune and stack it with something that adds more cylinder pressure and you take your truck's life into your own hands.
A good tuner (person who writes a tune) will get great power without creating pistons with nasty burn patterns, without creating cylinder pressures that will certainly push the head gaskets out, and look out for your best interest while giving you the most power that they can while trying to cover your bum. No tune writer wants the reputation as "the guy that blew my engine". He wants happy customers that will in turn suggest his work to others and scream off of the mountain tops about how great he is.
If you have a tuner that reprograms, such as the Edge evolution, and you tune it to the Performance tune, then you unplug and re-tune the PCM in the truck with the SCT programer/tuner.... All you did was put the Edge program into the OEM Stock position on the SCT memory and put the SCT performance tune into the PCM in place of the Edge tune. You gained notta, nothing, zilch. You can not stack programers/tuners.
When you get to the point that a stock truck (mechanically) can not satisfy you, dont look for the magic wand, look at upgrading parts. Injectors, turbos, intakes, exhaust systems, water meth, nitrous, propane, intercoolers, and more. There are ways to make even more power with a relative amount of safety.
I say relative, because there some degree of risk involved with racing and power. And dont kid yourself, the things that many of us do to our trucks are catagorized as racing/performance upgrades. When you raise the output, by nature you raise temps and pressures. To what degree you effect the life of you engine is in the hands of not only your tuner, but the vehicle operator. If you hammer the truck like a rented mule every day.... it will break. If you put a Silver Bullet turbo and 225cc injectors with a 2 stage nitrous set up and water meth injection on it, but you drive it soft and easy until there is a time that you need to drop the big gun, you can keep driving it for years without a great deal of problems, or at least the likelyhood of this is much greater.
Transmissions will only take so much. The 5R110 is a great trans, in my opinion the best "off the showroom floor" trans going. But it has a failure point! If your going to be living with 600+ RWHP and drive the thing like you dare it to break, it will! And it will break quick. Am I right Stump?
Some folks have begun taking the 5R110 out and putting the fully built 4R100 transmissions in. They can currently be built to ultimately handle more power. Most of us will not ever need to consider this project, but for some it may be the only logical way to go.
I know, I am long winded.... and I strayed a bit. But to make a point I felt I should cover the question with an answere that did not leave anyone wanting for more. I hope I succeded!