Re: So what drivetrain upgrades?
Unfortunately there aren't really any upgrades yet to the drivetrain. What are you looking for? You can get a lift kit or performance rotors or pads, but that is pretty much it. 17's won't fit with the size rotors and calipers we have. Not sure what you are exactly looking for, but there are plenty of larger tires available for 18" wheels.
I run 33" tires with the Quadra Lift system and almost zero rubbing, but I have done a few tricks to get there. Tweaking the fender liners to get a little extra room. I only rub when it bottoms out, but that happens more than I would like.
Pic of Jeep at Entry/Exit height.
2014 WK2 EcoDiesel LTD, Trail Rated, GDE tune, Offroad Exhaust, 275/70/18 Duratracs
2008 WK CRD LTD - GDE ECO Tune, 3" Intercooler, CBE exhaust, GTB2260VKLR, 3.07 gears
2007 WK CRD LTD - Max output, GTB2265VKLR, Long travel, wilwood brake 6 piston front 4 rear