After testing with multiple devices we have some more answers.
Headphones: beyerdynamic DT 1770 PRO
- Grace m9XX: still sounds awesome, current drop: massdrop: Grace m9XX
- Aune X1s: right behind the Grace m9XX for half the price
- Audinst HUD-DX1: a bit behind Aune X1s
In general the Grace m9XX just has the bass to keep you pushed and a magic clarity with which every song sounds different than before without it. Also the dynamic range is just more present and larger.