I agree with the others that shoehorning an older, used A/P into your airplane would not be a small undertaking. With that caveat, I've removed the stock Cessna A/P from my airplane as part of a weight reduction program since I never use it on low altitude surveys anyway.
The couple of times I tried it after I bought the airplane, it seemed to work 'OK' (held heading & altitude reasonably well, etc.). I have the control head, elevator and aileron servos, and master unit (from up in the overhead). What I don't have freed up are the wiring harnesses, although I'm looking to see if I can snake them out somehow. You're welcome to it all for a hundred bucks + shipping, with no warranty expressed or implied as they say. And if I can get any of the wiring out intact, I'd send that along.
Joe
joechr@msn.com