To me, the rear differential carrier looks like a *really* clumsy design. Why does it have to be this large and heavy and attach to points far away from the rear diff? Why not simply bolt the entire differential to the rear subframe, instead of just the two rear connection points?
The same R160/180/200 differential is used in other japanese cars, but they use a far more compact design.

I'm not an engineer, so please enlighten me!

 

Id assume the wide attatchment points would aid in stability, if the mounting points were close to the diff, it would be very easy to twist the diff off its mounting point, especially considering some of the power some people on here are running....

Like imagina a person lying on the ground with their arms out wide, and another person lying on the ground with their arms by their sides.
Which one is easier to roll over? In the same way apply this to a diff...

 

A great deal of the shape is attributed to working around the fuel tank.