I have a complete Brittain system in my '65 E model, with altitude hold and pitch control. For 4 years I have tried to keep it working, buying parts Others were selling, rebuilding servos, sending parts to Kevin in Tulsa, and doing extensive testing myself. You probably know there are very few people who will work on them, and even fewer who are FAA certified. The company is essentially out of business. Jimmy Garrison says that it would add $2000 to the value of your airplane, assuming it worked. It probably won't. It would definitely cost more than that to install, troubleshoot, and attempt to repair. I am getting ready to take mine out and install an aerocruze 100 aka trutrak. Cost is about $7,000 for a good autopilot, admittedly not as good as Garmin. If you are so inclined, you can install it yourself under supervision. If it were me, I would not waste money on a Brittain system.