Promitheus and Wyred4Sound

I'd be a little concerned with the 2.95V input sensitivity of the SX-1000 when using it with a TVC or any passive for that matter.

Yes Clio09, that is what I am thinking. W4S did mention that they can double the gain to 54db. The question is, will this sensitivity change make any negative impact on sound quality?
W4S also mentioned that with the current configuration of the SX-100 and TVC supplying 1.5V, it will produce 285W at 8 Ohms. If that is the case then fine. But I don't want the amp supplying 1.5V at the 20th or 21st position of the volume knob, out of the available 24 positions. I would rather have the 285W reach at 16-17th positio on volume knob. That way the TVC and the attenuation will give me the best sound quality. I may be wrong and open to suggestions.

Wow 54db is a lot of gain. I am not familiar with the W4S designs, but I'd be curious what that the input sensitivity would be in that situation. I think your concern with regards to volume control position are valid from a flexibility perspective and not necessarily sound quality. I prefer my settings around 12 or 1 o'clock for average listening volume.

The input sensitivity would be 1.5V as per W4S. Infact when I asked if the sensitivity can be made to 1.5V, they mentioned that the gain would then be 54dB.
You are right, I am more concerned about flexibility and I need more headroom (in case). With the NADs I set the knobs at 12'O clock position and I am already reaching the room limit. The NADs have 770mv sensitivity. The TVC creates a magic either at this setting or at +- 1 position from 12'O clock.

The new Musical Fidelity M6PRX also seems to have some great specs. But I have seen many folks 'goners not much happy with Musical Fidelity product. The M6PRX is a bit out of budget though:

http://www.musicalfidelity.com/products/M6-Series/M6PRX/M6PRX.asp