i have an rs2k 4x4 and as far as im aware they are meant to be able to handle no more than 180lbft of torque altough some may remember jason hodds red rs2k 4x4 which was running a 2.3 i4 turbo which was around 330bhp i think, and had no problems at all. his transfere box gave up when the new owner was trying to pull doughnuts from standstill at full revs