Advice on converting my VMC

[Proteus]

As i am a newbie compared to you guys out there, i really could use some good general advice.
I am about to rip out alle the electronics, steppers, spindle and PSU on my Boxford VMC300, and convert it for Mach 4 software.
My intention is to keep the orgiginal ball screws unless somebody here had some poor experience with them.(Plan is to change the later on).
The plan is to make use of the KL34H295-43-8A 906oz, Nema 34 stepper motors from Automation Technologies, with the KL-8070D Digital Bipolar Stepper Motor Driver-32 bit DSP Based from the same company for X/Y/Z axis.
As i plan for a 4/5th axis cradle, i have planned the KL23H2100-50 570oz Nema 23 stepper motors from Automation Technologies, with the KL-6050 Digital Bipolar Stepper Motor Driver-32 bit DSP Based.
570oz for the cradle might be a bit overkill, but i worry about the holding torque when the chips start flying.
The choice is based on me having experience with only these steppers and drivers from my previous BF25 conversion to Mach 3.
All axis will be driven by toothbelt and slightly geared.
Originally, the VMC300 is equipped with Ametek MAE HS200-3424-0170 Nema 34 steppers at 212,4Oz/Inch(from what i can see), and SGS Thompson GS-D500A drivers delivering 5 Amps peak at 92V.
I am also planning on replacing the origial RS520GR1000 spindle and driver to a more powerful spindle to increase the milling speed.
PSU... Yeah right.. What to choose.
Should i keep it at 24V industry standard to reduce possible noise, or increase it to 36, 48 or even higher?
The transformers installed is maked 220VAC/60-18-12VAC for the first transformer and 220VAC/120/115Vac.The last one for the spindle i guess,
Controller/BOB..
Should i choose Network, USB or stay with the paralell port type?
Advantages / disadvantages?
Besides i need something to communicate with the ATC.
(No, i dont need it. But it`s already there, so why not make use of it?)
Any comments or advice is higly appreciated.