As far as I know, Sonar has since 2002 had PDC in some form. It always allowed latency reporting from plugins to adjust playback to the highest delay in the path. As far as auxiliary and sub groups ouputs do have some delay if output is set to a seperate ouput other than master out, which is possible in other hosts, Abelton live comes to mind.
Is this a problem you have encountered or just out of curiosity?
One thing that is a problem though is how rewire is reported in MIDI timing, I have noticed in some vsti's and Appeggiators dropping sync after 8 measures. I believe it may be the Rewire protocol at fault due to it not reporting or buffering. May be something else altogether. Not a game changer, I simply load the synth and track in Sonar and everything syncs as it should.
Others may know more than I, hopefully they will chime in.