Ok so looking through this board I am starting to think I am the only person who uses a 4.8 NASA wing on my buggie.
to be honest its a realy stable and powerfull . built my own buggie and though about 6kilos more than bought ones still get great speeds with it.
I have a 6.9 I use for kicks sometime. The bad thing about the Nasa is its upwind ability, and overall speed. Its easy to "punch through"
(outrun the kite) A faster foil that will accelerate into the wind window farther is more desireable.