Gee, I had no idea the Summits were that efficient. Anyway, the 805s should be fine because the ML spec has SS amps in mind, and the 805s being single ended probably put out more effective power than their ratings. The real issue is whether they can handle the Summit's low impedance (0.7 ohms at 20K Hz) I'd get in touch w/ Cary and find out for sure.
BTW, you didn't say what kind of preamp you have but it would be nice (in terms of getting a little more effective power out of the Cary) if you could use balanced ICs to connect the amp(s)/preamp. And Cary does offer an XLR input option.
I do think the Summits lend themselves to the (right) tube amp which is wonderful w/ stats (but you already know that) but with the summits, you don't have to worry about providing power for the woofers.
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