Hey, surprised nobody chimed in yet. I don't think I'm going to be a ton of help, our front ends are quite a bit different and that's where the obvious restrictions begin. But the term restriction is really not all that.
If you're not opposed to working the plastic wheel well liner, and you don't go crazy wide. I'd guess you could tuck 35s underneath, maybe as wide as 12.5 but that maybe pushing control arm rub. 11.5 to 12 wide and I bet you'd be fine. (Seems 11" or less is a better choice)
And thatd be stock height, since you were gonna level with bills. If you went with a 35x12r20 and you did rub, the rub is going to happen at an area that you could do something about rather easily. We're talking plastic liner, or pinch weld modification or you could up your bils. Knocking out some pinch weld, it's easy, harmless and cures contact, plastic liner shaping is even easier.
I think worst case if you go wide 12.5 or above you might rub on your control arms at full lock. And then a control arm replacement is the fix, and I think you can do those for half the cost of a single tire. Can always spend silly amounts on high end widgetry but Unless it's gonna be landing gear I wouldnt think it necessary.
I would also say don't cut your plastic well liner, but instead grab a heat gun or a torch and rmold the liner out of the way, it's fast easy and still protects as much as possible. If necessary pop a small hole in it and somewhere in the metal behind the liner and use a plastic fastener to pull the liner back. It looks **** remains un cut.
Wiring harness behind them, use caution.
Are you wanting bigger than 35s? If so I'd definitely get more than my input or search might yield more exact answer for you.
'16 RAM 2500 pw with a badass Greene tune feed'n & Fire'n the 6.4L w 6spd / 5.13 AAM / 37" KM3 at -25mm / DOR / Alfa / Purple Cranium / z36 PowerStop / Custom Graphics / AVS / Diode Dynamics / 4% VLT Tint 
