On Monday, April 1, 2019 at 9:26:34 AM UTC-6, Michael N. wrote:

Are winglets and / or 16.6 extensions available for these aircraft?
Do you know of any for sale?
How difficult is it to upgrade / install?

Good note on the ASW20 extensions. So just looking for winglets on that.
I have seen people post positive experience with the 16.6 extensions on the Ventus B. So I am still potentially in the market for those. As well as the winglets.
I am looking at the M and H winglets now.