I wouldn't get hung up on the numbers, but you should be listening and making up your own mind. Spending that sort of money without doing so would be lunacy, and a dealer worth their salt ought to allow you to demo at home or at least take your own amp in.
I have auditioned the 702 s2 with Chord's Etude. Every feelings, dynamic, rytheme, transparency etc, I get from the HD800s, the headset, I can get from the speaker too. But as a speaker, I think I only get a touch of these feelings.
The Contour 30i provide simliar but a bit better result. Yet the price nearly doubles.
One thing is the bass from 702 s2 isn't that pleased when listening to classic music when tuning louder. I am not sure if it is for the speaker or the amp or the music source (Does number matters in this case, 4ohm, 150w vs 8ohm 300w).
As a bonus, when it comes to 805 D3, the difference is obvious in its very pleased warm feelings. However, this flagship, even as a bookself one, definitly needs larger and larger room to stream it's wave and to let audience to imagine.