DP3, Soft Synths/Samplers and Two Macs

I know this is been talked about before, but I was wondering if someone could explain what else I would need (hardware wise) and some of the pro/cons of using two Macs instead of throwing everything on one Dual GIG. I selling my last hardware synth (Fully loaded K2600R, anyone interested?) and going ALL DP3 and softsyths.

My setup:

G4 Dual GIG
Apple Cinema Display
1.5 GIG RAM
Two 80 GIG HD
MOTU 896
MOTU MTP AV
Mac OS 9.22

Version of the software:
- Digital Performer 3.0.2
- Free MIDI 1.47
- MAS 2.34
- Reaktor 3.0.5 Altivec
- Absynth 1.2.3
- FM7 1.02
- Battery 1.0
- B4 1.1.1
- Sample Tank 1.1.4

I have G4 500 with two 40 GIG HDs and 1 GIG of RAM just sitting there doing nothing at the moment.

(1) Would it make sense to move some of the NI stuff to the G4 500 (Kontakt, when it comes out, Reaktor, Absynth,....)

(2) If so, which combination would make the most sense
- Kontakt and Reaktor
- Kontakt and FM7
- ...........
Since the second machine is just a G4 500 how many NI soft synths should I use on it?

(3) What other hardware would I need (another display, etc....).
How do I get MIDI in and out and Digital Audio out of the G4 500?


Thanks for your help
Mike