Computer choice help

Hello,

I am building a BAe146 simulator and I am looking at purchasing some new computers.

My system will consist of one computer powering mostly USb devices...probably 26 to 30 usb connections for engine gauges and flight instruments...plus an I/O interface board (Leo Bodnars BUO836x for flaps, throttles, airbrake, landing gear, and a number of switches.

The second computer will be networked and will provide the visual system through three short throw projectors and TH2go.

I am looking for some information on what I need in each computer to provide the maximum performance with no degredation.

Thanks

-Jim