I owned a Speed Astir for over ten years and there
is still a Speed Astir on our field. I know of no
modifications for the Speed Astir.

There was a readily available paper on where to place
turbulator strips on the TOP surface of the wings.
I found that use of the turbulators significantly
improved the low speed handling in rough thermals.
Without the turbulators there was a tendency for the
inside wing to drop when close to stall. After placement
of the turbulators the plane was very solid into the
stall.

Guy