1 slight correction, the Q45 is a short nose R200. R230s are only from the Z32TT or Armada/QX56.
Axles are interchangeable between the Q45 and Z32TT. Q45's
Q45/Z32TT hub inside spline count is 32 (post #4 and post #41):
http://forums.hybridz.org/index.php?showtopic=35579
Arizona Z car also has a mustache bar that will work with the Q45 diff swap:
http://arizonazcar.com/diffmount.html