I can add a little data for the separated auber setup, during a bypassed #2 800watt element cook. When cooking whole, deboned & boudin stuffed chicken, I set my auber to 500 degrees. Once the box temp reaches 300+ degrees, I place the bird in the oven as well as the foil covered wood box & insert the IT probe.
The box temp will rise to a max temp of 460 - 465 degrees steadily. I don't know how high the integrated unit will allow it to be programmed or if its governed at all. Obviously, the separated auber setup that remains plugged into a stock unit (no bypass) will have a max temp limited to the stock unit 250 degrees
About 1.5 hrs later, I have very nice, non shrunken & moderately crisp skin and a fabulous dinner. I cook very seldom using this technique but the 6 to 8 stuffed birds I smoke each year are always done this way.
The moral of the story is how high can the integrated unit go? We know the other answers.
I was slow to convert to the auber & I still think it adds very little value for the standard cook. Due to the high temperatures here in Louisiana I use an external smoke generator (big kahuna) for cold smokes. I use the auber extensively for low temp smokes like fish as well as high temp smokes like indicated above. This setup allows ME an extremely broad range to execute proven smokes to MY liking. I would love the integrated unit if these capabilities can be reached. I hope I didn't muddy the waters too much for you. Good luck.
I have had my unit apart to bypass it, as well as to repair a couple of broken wire connectors over the last few years including a couple of weeks ago. I have noticed NO damage due to running it this hot but I believe it it NOT recommended by the the manufacturer. So take this technique for what it worth, my personal experience.