I would stay with the ht pro silways. The az silver ref does sound a little more open and detailed, but probably not worth the extra cost. Vandersteen speakers, not being hyper detailed, do not tend to benefit as much from the last 'nth' spent on ultra-expensive electronics. (one of their many charms - my current speakers are ultra-hirez audio physics, but I've owned several vandersteens).
A GREAT speaker cable for the vandersteens is the sumiko ocos.
Theils can verge on brightness. Haven't owned them, so can't help. Have heard they sound best with ultra-detailed, expensive front ends.
I would like to second Z's comments. Vandersteens do really 'come into their own' with certain solid state amps such as the mccormack dna-1 (far and away the best amp I've used with vans), or the 300w adcom 5802. If the van 4 is an active subwoofer design (like the 5's), you would be best served by the smaller, but sweeter voiced dna 0.5. I know I'm answering an unasked question, but I would spend the cash. If you can direct drive from that 1650 (most upper crust denons do if I recall), you could run direct to the amp and get great sound.
A GREAT speaker cable for the vandersteens is the sumiko ocos.
Theils can verge on brightness. Haven't owned them, so can't help. Have heard they sound best with ultra-detailed, expensive front ends.
I would like to second Z's comments. Vandersteens do really 'come into their own' with certain solid state amps such as the mccormack dna-1 (far and away the best amp I've used with vans), or the 300w adcom 5802. If the van 4 is an active subwoofer design (like the 5's), you would be best served by the smaller, but sweeter voiced dna 0.5. I know I'm answering an unasked question, but I would spend the cash. If you can direct drive from that 1650 (most upper crust denons do if I recall), you could run direct to the amp and get great sound.