Ideal Sub pairing for Quad 2805s

Looking for fast, musical sub that can keep up with the speed of the Quad 2805s. Heard that the Wilson Benesch Torus is an amazing pairing that works perfectly with the Quads and brings out the highs and midrange even more!
The only problem is that I don't want to spend $13k at this time.
Has anyone used the REL Gilbralter G2 with success? Intrigued that the carbon fiber drivers of the G2 may be fast enough to work with thte Quad electrostatics.
Any other ideas people have used with success? JL Audio Fathom f112 (certainly a great home theatre speaker)?
Did you say the subwoofer brings out the highs and midrange even more?
My REL Storm III mates perfectly with Quads.