Mark,
The Dynon units with the new HSI screen work well with the NMEA GPS signals. The problem is with the ILS/VOR functions since the Garmin AT (Apollo) SL-30 NAV/COM unit serial data is what the new software is designed to accept. You will find the discussion about this subject on the Dynon forum.
Luckily, I chose the SL-30 for my NAV/COM unit. The Dynon works great with it on the HSI page. The GPS data feed will give you winds aloft calculations via the Dynon HSI page. You can see that in the last photo on this page:
http://www.n2prise.org/rv9a231.htm
Jerry K. Thorne
East Ridge, TN
RV-9A N2PZ