Both the Horton and the VG kits were on my plane (337A) when I bought it. I thought that the VG kit was part of the Horton kit, but am not sure.
My stall speed at landing is about 7-8 mph below POH, and the thing flies as firm as a truck. The cruise speed is about 3-5 mph slower than POH, but that is without having things tightened up as much as possible.
Keven
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Vermont dispensaries