Consider Simrad autopilot
I installed a Simrad WP10 Wheel Pilot on my Hunter 31. Works flawlessly, best improvement I have ever done. Bought it at the AC Boat Show about 2 years ago for around $700. Probably can get it for $600 or less now. Took about 2 hours to install (by my wife and me), including mounting the unit at the wheel, wiring and circuit breaker. They also make a WP30 which is an upgrade from mine because it interfaces with your GPS/NMEA instruments. Remote control also available if desired. Nice clean appearance, waterproof design, easy to use, no maintenance required. No drilling or cutting required.