I'm still very comfortable with the additional electronics to add to my panel - the safety issues alone justify their cost. Contrast this with the other additions I considered such as replacing the gyro and pitot/static instruments with new solid state electronic stuff. The gyros are good enough for a day VFR plane, and that's what I consider Papa Golf to be. Deciding to ditch the King 89b and put both a new 396 and my existing 296 in the panel, however, might be a bad idea.
I originally thought the 89b would just be dead weight since having two other GPSs to use would really relegate the King to wasted panel space. I figured I'd get more utility out of a map box. I'm re-thinking that now, though.
I want to leave my options open for a Trio Ez-Pilot autopilot or similar, should I ever decide to buy one. This means I will need to reserve space for the control head, and it means that I will have to keep the 89b. The beauty of these new autopilots is that they are not based on inputs from the mechanical gyros, instead using a single onboard solid-state gyro. Mechanical gyros are to some degree somewhat untrustyworth, so removing them as a point of failure for the autopilot is nice.
To supplement the solid-state gyro, the autopilot uses GPS inputs. The 89b, being a true panel mount GPS, provides the outputs required by the autopilot. The Garmins I have do not. I still like the idea of having the 296 and the 396 since they both have nice color moving map screens, so to have all three GPSs I will have to forget about the map box. I also need to reserve space for a the control head.
I forgot that the EZ-Pilot replaces the mechanical turn coordinator too. That looks like this:
The old turn coordinator would work well as eBay fodder.