F/R Torque split on a hillclimber?

[el_tonto]

I'm gonna make a Formula Off-road style racer, and am considering the merits of a center diff (my truck will use Mad Force axles and a highish-power brushless system)

Lots of hillclimb trucks have loads of power and often end their attack when they wheelie over backwards. Obviously loads of torque at the rear wheels do this.

My options are -
Standard center tranny (i.e. locked)
Buggy center diff, probably with fairly thick fluid
Torsen center diff ($$$)
Front torque bias (e.g. 70/30 torque split)
Rear torque bias (e.g. 30/70 torque split)

The easy way to do the last two would be a higher power motor for one axle and a lesser-powered motor for the other. So technically it's trivial to do any of the above, but which is going to be a better hillclimber, all else being equal?