Welcome! Your airplane certainly did have a distinctive scheme!
I read somewhere that the window removal was done for the FBI, when they owned the airplane.
In regard to the windshield heat, I remember that as well from my long-ago Merlin days. In Commanders, the issue is that they tend to fog up in cold temperatures, so turning the heats to LOW at FL180 is an easy solution. There is a small amount of visual distortion with the heat on, which is why it's preferable not to run it when you are VFR.
In regard to the Sundstrand, personally I really like it. It generates air immediately and in high volume (so fewer pressurization issues than Enviro). If you are in a hot climate, a freon system makes a nice addition-- I think freon and Sundstrand is the best combination.
There is a thread in this forum on care for the Sundstrand, so I would take a look. I think it's in the "Environmental" section.
Short answer is:
1) Never, ever, ever, ever turn Max Flow on. Let me repeat that: Never, ever, under any circumstances, turn Max Flow on.
2) The AFM recommends adding oil every 25 hours. Unfortunately, there is no way to check the oil-- the only thing you can do is put more oil in until it spills (literally described in the AFM as "fill to spill").
3) There are some filters that need to be changed every 300 hours. They are absurdly expensive. Change them regularly.
I'm attaching the AFM page which shows the different units and how to add oil. Unfortunately, it's not really a pilot-accessible task-- it requires opening up the baggage compartment.
Please ask away with any other questions that come up!
