I had professionals install my Simrad AP-16 in my 228.
They put the compass way forward inside the starboard side cabin storage compartment. And I am careful not to store anything metal on that side (like a spare anchor chain - which I keep in my port side compartment).
The computer is on the inside of the cabin mounted on the starboard side bulkhead. Near but below the starboard side window but on cabin bulkhead.
The pump is behind the interior wall, bulkhead, below the steering wheel. That "L" shaped wall thing was taken apart and the pump was mounted to the inside of it (I think).
In any event, my auto-pilot is invisible except for the computer on the inside of the cabin. And I love the darn thing. Can't imagine not having one. Good luck. - Jack