[jclark003]

A little more information may be helpful. What model raymarine AP are you trying to replace and what type of system are you trying to interface with?

Generally speaking if you have a reversing 12v or 24v pump in the current AP system and want to switch autopilot computer/head there is no need to break into the hydraulics. Just wire the motor into the new AP computer. This can usually be done with any autopilot system (Garmin, Furuno, Raymarine, etc). Also most autopilots send and receive navigation data using NMEA 0183 or NMEA 2000 and as such can be interfaced across most manufacturers head units or MFDs. If you like the Garmin AP and aren't sure of compatability then give their support line a call and I'm sure they will give you everything you need to know.