I just doubled the 8Ohm usual spec that is the easiest to find when reading through spec sheets.

The 3808 is capable of 238W into 4 ohms according to some lab tests. So you would need a ~500W 4ohm capable amp to derive easily heard/loud benefits. This is where the Emotiva amps come into play, as they are the lowest priced amp, it seems, with these kind of specs avaialble.

Jason
M80 v2
VP160 v3
QS8 v2
PB13 Ultra
Denon 3808
Samsung 85" Q70