Hi,
The amp modelling software is the same regardless if you use a GuitarPort, TonePort DI-Bundled, POD Studio GX/UX1/UX2 USB hardware device. You'll be able to use either GearBox or POD Farm modelling software, depending on what your needs are.
However, you won't be able to use your computer's speakers to hear the modelled sound as that output will always come from the output device of our USB device(s). Many new users ask this same question; I usually try to get them to understand that our USB audio interfaces handle both input and output for audio, once the USB drivers have been installed and the USB cable is connected.
Regards,
L6Perry