Thanks for the replies.
I thought all skymasters with autopilots had the 400a. I didn't realize there was a 400 IFCS option.
How do I know which I have? Looking at pictures online, it looks like I have the 400 IFCS (it does have flight director buttons on the panel). If so, I think that simplifies the garmin options because it appears to be on their list of supported autopilots whereas the 400a is not?
This is a pic of what I currently have:
Cheers,
and
Happy new year everyone!