280,000km original stock box, no problems at all with mine! Then again, the torque from the V8 is only up a small amount compared to the six (around 30Nm?)
EDIT --> Don't the AU XR8s have the same box as E-series? (Apart from the adaptive shift) If so, their power vs standard E-series vehicles is a significant difference
EDIT (off topic) Join "ATPS", add it to your sig!