Trutrak was the plan.
An ADIPilot II was what I was planning. Alas, financial considerations made me postpone my autopilot and efis. I finished the plane VFR, with an eye to upgrade it later.
Recently, a fellow forum member sold me a used Navaid with servo and coupler and hardware for $650.00. I installed same Monday.
While I have not heard a lot of good things about Navaid, this one has worked flawlessly in the 8 hours or so I have flown it so far. It tracks well, intercepts and in general is very smooth. Installation was very simple.
At the top end are the certified A/P. Way too much money. Just under them are Trutrak and Trio. Trutrak has more products geared towards IFR airplanes. Trio has more features for the buck (IMHO).
YMMV