I'm not sure where you're trying to go with such an inane example. The M50's soundstage and imaging are not (verbatim) "quite good compared to other headphones in the price range" - "headphones in [that] price range" with significantly better soundstage include the K240, AD700, and HD555 (though none of these can satisfy basshead yearnings). The M50 fared poorly with classical music: while it had the speed to keep up with the sonic demands of classical music, the soundstage/imaging left a lot to be desired. The cluttered soundstage and poor imaging are shortcomings of the M50; they are not - as you put it - "quite good."
I truly appreciate your efforts in making such a comprehensive guide for bassheads on a budget, but I implore you to accept sound criticism when it's offered.