There are plenty of used Beech Baron twins on the market sporting 1980s-vintage analog autopilots and the spinning iron gyros that drive them. It takes effort and money to keep these systems flying right and tight, easing the decision to spend serious money for new glass with a digital autopilot.
After a long engineering and certification effort, Dynon has a fresh STC for retrofitting the SkyView HDX Certified suite in the majority of the Baron 58 series. Garmin has owned the Baron upgrade market with the G600 TXi displays and GFC 600 autopilot. Here’s a summary of the Dynon interface, which is nicely scalable depending on the budget.