Here's the answer
:
AWD models have a 55mm factory offset on the 18x7.5 wheels, whereas the RWD models use offsets in the 15-25mm range.
The AWD models have the front brake calipers mounted on the front of the rotor, the RWD models have the calipers on the back side of the front rotors
The stock AWD suspension sits 1" higher than corresponding RWD models.
This can be "fixed" via Eibach springs (2" total drop after settling), KW coilover kits, and the soon-to-be-released CW Motorsports coilover kit, which I will be looking into getting as soon as some are on the road and people are happy with them. The coilover kits are adjustable for drop and the CW will also be adjustable for ride smoothness (not sure if the KW is)
The car's floorpan, the engine oil pan, and front struts are also different on the AWD models.
The floorpan has a hump on the right side so the transfer case can fit.
The front differential is mounted on the right (passenger) side of the vehicle next to the engine and has an intermediate shaft that goes through the oil pan and connects to the left axle shaft (the right shaft connects right to the differential).
The front struts have a lower "fork" which connects to AWD-specific knuckles and the fork allows the axle shaft to go through it to connect to the center of the wheel
The front brake set-up (shows my current rotors - drilled/slotted R1Concepts) :
The front diff, oil pan, intermediate shaft :
The AWD front suspension:
(ignore my leaking CV boot
)
The transfer case :
