Lol don't read too much or else you are going to believe everything they tell you. From my experience when I tried the HD598 which is similar to the HD558 is that it has really good soundstage and focused a lot on the mid's, I like mid's lol. But comparing soundstage with soundstage, the X2 falls behind by just a bit, I could tell the difference but in no way did it actually affect immersion.
I feel like the X2 still has pretty good imaging for the type of sound signature it offers. You won't lose immersion at all if that is what you are looking for and you won't lose imaging either while still having that bass from explosions and stuff.
But if you really need that competitive edge, just stick with the HD558 or get an HD598 or an AKG K612, but you will lose the immersion since the bass is reduced and the mid's are more noticeable while giving an airy sound.
All grounder for immersion and still give you good positional audio, X2 is the go to headphone.
Just FYI, don't expect the headphones to make you a better game or increase your KD by a lot lol. Your situational awareness will improve and maybe you will save yourself from a death or 2 or get 3 more kills but just enjoy the sound because it makes gaming so much better.
Heck, I can own in a BF4 server without even using sound