Responses from hk_fan

Tube Pre/Monoblock Recommendation
In my opinion if you own Merlins you really should pair them with Joule Electronics. That's what you will find being displayed at EVERY show and the sound is simply outstanding. 
Power Amp advice
I use Parasound JC1's with a ML 326. Fantastic combination.Of those you listed the only one I'd consider would be the Ayre, but I'd still choose my JC1's over it. 
What is the best sounding DAC at $2000-$4000?
The Ayre QB-9 is an excellent choice and fits within your budget. 
Amp Advice : to Proceed or not to Proceed ?
If you can buy the HPA 2 for $500-$800, buy it! Nothing else will come close for that price. 
Need at least 900wpc in 4ohm
Parasound JC1 testing from Stereophile:With continuous drive, the Parasound clipped at 545W into 8 ohms (27.4dBW)¬óway above the specified 400W. ("Clipping" is defined, as usual, as the power level where the measured THD figure reaches 1%, and is s...