Just because the HE-6 doesn't clip does not mean they are getting optimum power. I think something like Parasound's 45wpc Zamp v.3 for $349 might represent the best price/performance for the HE-6. Some other outside-the-box options could include something like the all-in-one NAD L54 for $400, which includes 50 wpc, a DVD source and auxillary inputs, or one of Bryston's Premium Speaker Switching Boxes for an existing high-end speaker rig. The Peachtree DAC/speaker amps could also be interesting with the HE-6. My Alesis RA100 would be a really good bargain as well if you can find one, but I bet many pro audio NFM amps would work out great.
BTW I find the soundstage of the HE-6 pretty coherent out of the EF5.
Edited by grokit - 11/18/10 at 5:59pm