I don't know what is the fastest, but I think the Vampire is pretty fast...but I have been flying only GTi and Vampire.
Two weeks ago I got 58 km/h vertical average while flying faster horizontally than our Cessna 206 on jump run.
I left the plane early on the jump run and I was flying straight along the jump run, CRW jumpers who jumped one minute later told me after the jump that I was clearly overtaking the jump plane. Cessna was flying 80 kts indicated on the jump run.
So the glide ratio for the whole jump was over 1:2.6 (probably closer to 1:3, but I don't know how much faster than the Cessna I was flying)
And I know that I am not able to fly the Vampire to its full potential yet... It is so much speed and glide