Hi GA, can't imagine why you're interested in this subject.
The lounge is quite nice, but doesn't have showers. There aren't in any BCN at the moment. When the new *A terminal opens next year, that will for sure be a different story, but for now you're out of luck I'm afraid.
As BCN is all in a single terminal, you'll be able to access the lounge on your connection no problem. It's located near the center of the terminal near the 30 gates. Just follow the signs to "Sala VIP".