Interesting..... I'm guessing the only benefit of monoblock calipers is that they weigh less then the split calipers?

Lighter and simpler but more costly to make. They have better wheel clearance as they can be thinner around the perimeter as they don't have bolts holding them together. I suspect they may also be stiffer as they're one piece of material, compared to two halves bolted together.

I'll compare the weight of the various calipers later :)

I came across this link about monoblock vs. two piece calipers.

Very interesting. So I was dead wrong about stiffness then :D The trade off of reduced weight is flexibility of the caliper. With the D2 brake system already being pretty spongy, I wonder what effect the Porsche calipers will have on it...

I wouldn't be too worried, most of the D2's sponginess comes from firewall flex (speaking of which, where are we at with the master cylinder stiffening blocks?).
And all the deflection/strength ratio problems in racing will be less so in street applications where the rotors are smaller, the calipers are bulkier, and the heat is lower (except perhaps on a track car).