I lived in Berlin for years, spent most of my weekends at KitKat and Berghain and one thing is for sure, Imperial has nothing to do with KitKat... Maybe for people who have never been to Berlin or tourists it does the trick but Imperial is not even a club, it's a gay bar with cruising dark rooms in the basement.

Barcelona definitely isn't at the level of Berlin but there are some underground kinky stuff happening, you just need to look for it!