I went with the model 30 because panel holes are always scarce - maybe
I want an electric AI some day.

I also installed the GPS steering with my Garmin 430. I programmed a
flight plan a while back with a 160 degree turn, and it was just
awesome to see the system handle that with maybe only 40 ft of altitude
adjustment.

I also have the DG connection, but the GPS connection is just the best
thing ever.

The Model 30 also requires that you be within 10 degrees of the
localizer heading before you engage it. It's absolutely solid on track.