Hi,
I tried using my psr as a controller for my SD2 sound module.

Psr couldn't send the correct upper bank & program changes.

( I wanted to use it for extra melody voices for the psr)

Unfortunately SD2 has no buttons, what so ever. It wasn't a good combination , at least if I'd been able to choose sounds on the SD2 itself, it would have helped. On the other hand, my korg PA800 worked perfectly. It sends any bank & program changes required.

If all you're trying to do is use the T3 as a controller for multi track recordings on a workstation (ie record one track at a time), don't see why it wouldn't work.

Are you mainly adding a workstation for additional sounds? because for as little as $50 or so you can get pc sequencer software.

Even though my PA800 has a fairly good sequencer, I still prefer to do any midifile editing in a pc sequencer. My PA800 is permanently midied to my pc or a laptop. Unfortunately my SD2 died, so on occasions I midi the PA800 to my PSR and use the psr as a sound module. Could possibly do it vice versa, but I'd probably have to to choose the sounds manually on the korg, which would be a pain for realtime arranger playing.

My last full workstation was a Korg O1W ( early 90's ) also had a Yamaha QY700 for a couple of years or so, it was great in it's day.