yes I tried and didn't show any update for DVDSP4, but is it safe to update, I mean, does everything will keep working in the DVDSP4? (like opening previous version projects 4.2.1)
I've kept Leopard because of update problems to Snow Leopard and stoped doing ProKit updates too. I still work pretty well with Final Cut Studio2.
Should be ok, but I strongly recommend cloning your startup drive before you do the update. That way if there are any problems, you can restore your startup drive to the previous state.