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200 watt receiver and 90 dB/w/m speakers and need more juice? Man get your hearing checked.
As far as streaming DAC's go I'm a fan of NAD - Node 2i ($550), C658 ($1650, Node 2i "on steroids"), M10 ($2750, Master Series value leader, includes a 100 wpc stereo power amp). The C658 and M10 also have Dirac Live (DSP room correction) built in. No preamp, computer, or additional software needed for any of them.