I admit, I am skeptical of the Zuki's, why not just buy original SoundStreams? I have played with a few Arc's, great quality, but I feel the pricing is high and most models only accept 4v signal. The Zapco's are some of the best available. The Sundown SAX-100.4 beat out some Audison's in a comparison last year. The US amps AX models I have been around in the past were awesome. Maybe you need to see if there are any certain features you need. I believe there are a few ESX 4 channels floating around. Consider seeing if there is a Draconia up for sale, but people don't sell them unless they are forced to. I know there are a few Diamond D7 fans on here. And for good measure, look at the Lunar amps too, not pretty but outstanding amplifiers. As you see there are numerous options, just need to start shrinking down the options.