Should I buy this 2,000$ A/D D/A Converter? Will I notice an improvement in sound?

[BertKoor]

Yes, but I'm reminding you this topic sits in our "Getting Started" section

[Jorgeelalto]

Does anybody upgrade from cheap to expensive notice big difference?

I've. From $200 to $2000 interface that considered a mastering audio interface.
Noticed a difference of course, but it's not huge. Not snake oil.
Mostly more balanced sound, deep, high clarity on transients in all frequency ranges.
If you're planning to get mastering monitors, then it worth it.
Otherwise get a mixing audio interface, but not the cheapest like scarlet.
I'm talking about D/A. In A/D there should be much more difference, but I haven't checked this.
By the way, interesting comments above. I bet most of these guys have never worked on a $2000 interface.

I personally haven't worked on one extensively but I have been to several studios that use HQ everything (DAC, monitors, cables, etc) and the difference is there. But my impression is, if you need to ask whether it makes sense or not, it probably doesn't. It is a good thing to have, and maybe I'm underestimating the listening capabilities of the OP, in that case, I'm sorry.

[imrae]

I'm thinking of buying an RME ADI-2 PRO FS, my current interface is Audient EVO4.

Would I notice a different in sound? Is it snake oil? Would I be able to make better mixing decisions?

Tell us more about your room treatment and monitoring.