First when I saw a pic of the V8 I didn't see typical speaker level inputs but I saw something else indicating it did have them, and now looking in the manual it accepts banana plugs for the speaker level inputs rather than the typical clip type inputs. FWIW the PDR 80 does not have any speaker level inputs or outputs, altho you could conceivably split your L/R line signal out of the pc (assuming you're using a 2ch analog output rather than a pc with multich outputs including a sub) to both the integrated amp and the sub.
Typical active subs do not power speakers like a Logitech system or other computer type active systems if that's what you were thinking. Although with the speaker level inputs on the V8 you could string the speaker wire first to the sub and then split it off to the speakers from there (the sub just takes the signal, the amp still powers your speakers). You can review the diagrams in the V series manual here
https://www.paradigm.com/index.php?controller=attachment&id_attachment=86&display=inline