Garmin GPS-20A for ADS-B Out Capability

I just read the GPS-20A overview on the Garmin website. It emphasizes connecting it to a compatible transponder and G3X. If you don't have a G3X you still need an indicator on the panel to prove it is working properly -- so that is another expense. It connects to a transponder and G3X with an R232 serial port so make sure your transponder will talk to it. Still it might be a reasonable ADS-B Out solution -- just takes more research.
I have decided to go down the Appareo Stratus path. I already have the Stratus 2S ADS-B IN box that connects via WiFi to my iPad Mini running Foreflight Pro Syn. The next and last step is to buy an Appareo Stratus ESG Transponder for ADS-B OUT. It replaces the current transponder, comes with a GPS antenna, connects to the current transponder "L" band antenna and uses the iPad as the indicator panel. Appareo just started taking orders for the $3,500 ESG for January (Experimental) and April (Certified) delivery. It connects via a USB Type C cable to the Stratus 2S feeding both power and GPS signals to the 2S. So once I have the ESG transponder, I can hide the 2S under the panel out of sight.
I have a 10-15 yr old Trans-Cal SSD120-30A encoder which is connected via a parallel port to the transponder -- 10 altitude wires plus power and ground. I am going to replace it with a $350 Trans-Cal SSD120-30N-RS232. The new encoder is smaller, lighter and connects to the ESG Transponder through an RS232 serial port, 5 wires total I think.
So Jasperfield has one path and I a second -- anyone else study the hardware out there come to the same or different conclusion?