There is a DSP in the UX2, because the cpu load is very low when I use only Gearbox to record. If I do the same thing with a vst the cpu load is much higher (I tried with Guitar Rig), higher latency too.
Be that as it may, all the info I can find either from the Line6 site or forums, or third-party reviewers, seems to indicate that there is no actual DSP onboard the Toneports.
I suppose Line6 might have simply written more efficient software! :)
I'd love, though, to see a "SuperPod" that was actually aware of popular recording apps like Logic/GarageBand, Cubase, Cakewalk, Ableton, and would actually interact with them to record dry-tracks to disk but provide off-board DSP for recording/playback and mixdown. That oughta be possible without rocket science, but the amount of partnership required between Line6 and the various recording-app software houses would be insurmountable, I think!