It takes some fiddling, but it is possible to export the MIDI files from Sonar and import them to Sibelius. I just generally bite the bullet and go the other way (i.e. compose in Sibelius and then import into Cakewalk and voice). Last time I did this was with X1 and Sibelius 6. I'm considering upgrading to Sibelius 7 for an upcoming project, as they have a much better playback engine now...I previewed at a buddy's setup. For big band or orchestra, it's remarkably good....the playback captures notation, dynamics, etc...I would love to have a capability that seamlessly combines the best of Sonar (input and editing) with the best of Sibelius (publication-ready scores and now, exceptional instrumentation). I'm not willing to go back to Pro Tools to get it, though. I was unaware that Avid had acquired Sibelius.