

As for the driver: that depends on what you are looking for, i. e. at home / studio use, mobile etc. If you have high-end headphones, you probably also want a high-end DAC / amp.
For desktop use, the Chord Mojo 2 is great, but that’s a $650 investment, and probably not matched with the (still excellent) Beyerdynamic headphones (in terms of what I’d expect people to invest if they’re looking at those headphones).
A portable option (nothing stops you from using it at home though) that also includes Bluetooth (naturally, with LDAC) is the Qudelix 5K, which comes at around $100 and sounds excellent (even better if you fiddle with the EQ in their really decent app).
The higher impedance in itself means nothing at first, apart from the fact that you need more power to drive it. However, if your equipment is well matched, you typically get less distortion at higher volume levels and better treatment of frequencies, i. e. more clarity and better reproduction.
If you find your equipment can’t really drive the higher impedance headphones and you’re not willing to shell out additional funds, the low(er) impedance versions are still great headphones.
I’d pay extra for that