Still on the hunt for the perfect M20 (E / F / J) and have found numerous autopilots in the older planes that I'm not familiar with (The STEC A/P's I understand - mostly). I "grew up" in a Grumman AA5 with no autopilot and fussy "trim tabs" (extensions on the aileron that you had to bend by hand), and while I did my entire Instrument training in that plane, I hated flying in IMC, as you couldn't relax your scan for more than an instant without it wandering off one way or the other. I'm not doing that anymore. So now, 16 years later, I've had a little bit of experience with an STEC in the club 182 - GPSS, approach coupled, vertical speed hold, automatic elevator trim -- it's pretty sweet. And I'm pretty sure I need most of that same functionality in my M20.
Could someone give me a brief rundown of the various types, capabilities of each and whether I should steer clear of any of them in particular? What I've seen so far, I think:
* "PC" - Seems like a rudimentary wing leveler. What else can it do?
* Brittain "AccuTrack" and/or "AccuFlight" - Sounds like maybe an add-on to the PC?
* Century I, II, IIIB, etc.?
* Am I missing any?
In particular, I'm trying to understand which of these can:
* Track a heading bug
* Track a CDI
* Be upgraded for GPSS (I probably already know that answer)
* Be fully approach-coupled (I think I know that answer also...)
Can any of the components (servos in particular) be re-used if upgrading to a more modern autopilot?
I see some folks advocating for de-prioritizing the A/P on a purchase and instead planning to install one of the newly available (or soon to come) autopilots. Any ideas on installed cost for any of the newer systems? I'm guessing $15-20AMU?