The BossHifi B8 is an amazing headphone.
Build quality, detail retrieval, relatively flat frequency response, and large (wide) soundstage... all categories in which I'm confident that the B8 is among the best of any sub-$200 closed-back headphone.
Having said that, their uncomfortable, sound-gimping, stock pads absolutely must be replaced. After extensive pad-rolling, I found that using the Brainwavz Oval MicroSuede Pads result in the tightest, most-extended, and flattest bass, with the most-refined treble and imaging. For a larger sound-stage, choose the Brainwavz XL MicroSuede Pads which feature a larger, circular, ear opening.
Compared to using the MicroSuede Pads, the Brainwavz XL Hybrid Pads result in a more-spacious, richer, warmer sound... slightly brighter, but with less detail. The sound-stage is wider, but precise imaging suffers a bit. Center imaging is still excellent, though, especially for vocals.
Brainwavz Oval Sheepskin Pads installed result in a bassy, dark sound... still quite cohesive and enjoyable for pop music and general listening.
Keep in mind, I have modified my B8 by adding internal dampening material to tighten the bass (see below). I recommend installing XL Pads only if you secure them with 1-2 mm of padding material. Otherwise, the pads are prone to falling off due to their over-sized round size pads being a bit big for the more-oval-shaped cups of the B8. Having said this, the sound you are rewarded with might just be worth the slight inconvenience, especially for home users.