a Xeon doesn't help much (SU is not aware of), 8 kernels don't help much (SU is single threaded), a Quadro FX doesn't help much (SU uses OGL v1.5), 16GB RAM doesn't help much (SU is 32bit)... simply because SU is not taking advantage of it.
the fastest i7 (in the sense of clock frequency) and a mid-range GeForce delivers the best bang for the buck, nothing else.
Norbert