Robert M. Gary wrote:

GPSS can now be added on to most of the STEC pilots as an additional
box that sits behind the panel. What you really start paying for is
pitch.

Yep, my original plans were for the STEC 30 but by the time I got
around to putting in the alt. hold, GPSS, and electric trim (which
I really liked in an Arrow I used to fly with it) you might as well
upgrade to the 55X.