I plan to purchase a portable 8000 watt generator with a 30 amp outlet. (1) Will the 8000 watt be a problem? (2) Is 10/2 or 10/3 wire required?

The 8000 Watts of Power with a 30 Amp-Outlet should Not be a problem. Typically these 8K Watt (Continuous) 10K Watt (Peak/Starting) have a 30 Amp Breaker for the L14-30R Receptacle on the Distribution Panel of the Generator. So while the Generator can theoretically supply 8000 Watts of Power (32-Amps), this 30 Amp Breaker limits the Power Output to 7500 Watts at this Receptacle. You can also use the 110/20v 20-Amp Outlets and/or the 50-Amp 120/240 4-Prong Outlet, if you wish to push the Power-Output to the 8000 Watt Limit. And if you plan to use the Generator for both 120/240 Volts (Single/Split-Phase), then you will require the "10/3" Wiring. Be advised that "10/3" Wiring equates to three (3) Conductors, (typically Black & Red for Line-Power, White for Neutral/Return for 120-Volts), and the "NON-Conductor" Green or Bare Copper for Safety-Ground. Hope this helps.