Hi Mike,
As Face said it does have balanced inputs. I've never used them so I can't say how well it has been implemented. I can bring my pre-amp: Tom Evans Vibe (just the pre with the regular power box, not with the pulse, some day........)
I may come on the early side, I would really like to hear the Tannoys with Naim. As far as the W4S on them, digital watts are not as powerful as SS or tube watts - so the W4S's 250 a side is not as overpowering as it might seem on paper. It might be interesting to hear how the amp effects the Tannoy's bass performance though.....
Gregg