All good questions.
I want to get a GPS. Maybe just update the DBs in KLN89B. But traffic other than iPad would be nice, too. So, I figured, if upgrade the GPS then to WAAS capable.
Yes, and no. I really like the "steam gauge" look and I think I want to keep this look, at the very least something similar to what newer Mooneys have (but removal would shave off some weight). However (see below).
Flat screen for some odd reason doe not appeal to me, but I do realize the extra real estate is valuable and three GI 275s (horizon, hsi, and eis) make it very close to one big screen -- hence I think it may make more sense to have one big flat screen... If I end up with one (or two) big screen do I need 750+650 instead of 650x2? I am not trying to save money here, but rather panel space for non-remote audio panel and ads-b with real buttons.
EIS -- if I go with digital, I would like primary. Which can be displayed on the big screen (MFD/PFD?) from what I was able to dig up.
Modern AP -- yes, down the road, not right away -- KAP150 works.
The Garmin option is just an example. Dynon website does a better job, but still muddy for me (and lack of AP...)
I got a quote for 750+650+remote panel + remote ads-b from one place, two others I asked for quotes are mum. Money is always an issue, but for now I'd like to have a better understanding what my options are before I start talking to an avionics shop: in my experience it's better to know about 80% of the answer before asking questions.