Titanium HD has the usual line out (all features of the headphone section work over line out, like CMSS-3D) which can be used for any active speaker, amp or whatever, in your case the O2 amp. It will work in Windows 8 as well. I had no problems.
SBX is NOT THX rebranded. Apart proven from a lot users you can't just rebrand licensed stuff and get away with it. There's also a reason why Creative calls it OEM on their webseite and THX is still listing it.
What you lose with SBX is perfect legacy, what you gain is much better signal quality, in general through all virtualized channels, especially noticable with voices and music. You can for instance enjoy the soundtrack of a game much better.
Try to see SBX like a hybrid of CMSS-3D (imaging, depth, soundstage) with THX (tonality, sq), excep that CMSS-3D can be more accurate due to it's different EQ (which you can replicate with your SBX though) and superior in older games, though not by much anymore.
Today's games however won't ever go the old route again and it's pointless to have any hope in that regard. Let's see what "True Audio" by AMD brings to the table as it's supported by actual games.