One thing is for sure, the climb gets no better.
But there is an interesting effect that few people are aware of:
Higher speed means higher Reynold's numbers accross all of the wing,
in direct proportion. Higher Reynold's number generally means higher
efficiency. Therefore, there may be some small improvement in the
glide angle.
I recall vaguelly that some model of the Ventus is quoted with an
extra 1/2 point of L/D max at maximum ballast.

regards

Vassilios Mazis

Greece