Best integrated/power amplifier under $6000

@audiotroy 
Looking for either a power amp or integrated amplifier with at least 150 watts in 8 ohms for under $6000- new or slightly used.

Gato 150, BAT VK-3000SE Integrateds 

What is the rest of your system

Some people love Boulder others find the sound too sterile. May want to check out this unit.

https://www.audiogon.com/listings/lis9d497-boulder-865-integrated-solid-state

Im going to be using the RAAL SR1a headphones that need a minimum of 100w into 8 ohms to shine. they were tuned on the Benchmark AHB2 so that would seem like an obvious choice but considering other options as well (and a bit more power/headroom so I mentioned 150WPC - but I could also run Benchmark AHB2 monoblocks)

Having heard the Parasound A21, I don't really like the sound by Parasound  much. Other amps that Im considering are:

-Chord CPM2650
-Anthem STR