Final Audio Design Sonorous IV Headphones

I've heard really good things. Most complaints read to me like people thinking there will be problems going into it, searching for those problems, and convincing themselves they're there.

Because some problems in Euro market, Final Audio Design rename the Pandora series to Sonorous. As some of you might know, Sonorous III will be launched after few months, it looks just like Sonorous IV but has only dynamic drives. Nowadays, Sonorous IV should have the same ear pads as Sonorous VI (I'm not sure about that, because FAD changed the ear pads for several times). In addition, Sonorous VI is obviously different than Sonorous IV, that's because the materials of shell. Specifically, Sonorous IV has more bass and not as transparent as Sonorous VI (*also less detailed) . Thus, Sonorous IV is better when you listen to some pop music and it is way lighter. Personally, I would like to say it sounds 'cheaper' than Sonorous VI because Sonorous VI has very fine tone. Hopefully it will help you guys.

Can someone explain to me the difference between these the 4's(IV) vs. these much easier to research 6's (VI) that dropped a few months back: https://www.massdrop.com/buy/final-audio-design-sonorous-vi-headphone?mode=guest_open Besides the "final" brandings on the sides, how much different are these two versions. I mean they look exactly alike.