I think the best way to get high quality music (Flac, Wav) is to buy (used) CDs and rip them.
However in most cases 320kbps is sufficient and you can get them for pretty cheap if you look around.
In my case I get lossless when I can to future proof, but when I was looking for a headphone, I didnt want it to be super resolving.
There arent that many headphones that have that much bass that can also be high resolution.
I think you'll be happy with the M-Audio Q40+ZO2 amp if you find the looks acceptable. Its very neutral in the mids and highs and has extended lows with an amp. Im pretty sure they could surpass the amount of bass on the pros.