I have been running Zed amps for a couple of months now and feel they are worth every penny. Only downside is size. They are not a small footprint amp.
Go Zed and don't look back
Orion built Hott set up 15 D4 (same specs as DVC xtr or cobalt). I could do for $65 shipped.
Or
Elemental designs 13K also D4 for the same.
Both are pretty efficient.
Jason