Hi!
I have a 1.6ghz HDD Rev. A and have used the Xponent and Torq for nearly one year. I did the upgrade to Torq 1.5 also. Never had a problem. And no need for optmizations -- I've never turned Airport off, and I leave MobileMe Sync and Time Machine turned on all the time.
The only difference you may notice is that the waveforms won't be that smooth as they should do on your MBP, and that's because of the onboard video -- the same happens on other MBs that have Intel video.
I've given up my Xponent for personal reasons, but I also use Serato Scratch Live on the same machine with no problems.
You may find a little trouble if you try to use Traktor/Traktor Scratch Pro, but I believe it's a software problem, since my MBA runs Traktor 3 just fine. But then again, you can disable some features like time stretch, 4 decks and FX and it'll run great.
Also remember that Torq has an Economy Mode option which really drops CPU usage, and you can always turn off some features (Airport, Time Machine, MobileMe, Spotlight, Sharing). If you do that, you won't notice the difference.
Last, if you plan to buy a Rev. B, then forget all this non sense, and just buy it.
