Hi!
I also applied at BSA (Germany) and had collected some information online and from friends and other connections/forums.
Interview:
First, there's a normal phone interview. If you pass that, you will get invited for the case interview at BSA. There will be 2 rounds in the typical case interview format (personal fit, case interview...). This is for the entry level. For the level of senior associate, you will additionally have to do a presentation.
Reputation:
BSA was #1 hidden champion 2015 (http://www.berylls.com/en/hidden-champion/awards.php), they won the Best of Consulting 2016 award in a category (http://award.wiwo.de/boc/rueckblick/). I recommend you to go thru their press releases on their website, it contains loads of information.
Starting salary:
The starting salary is according to industry standard.
Requirements:
You have to be passionate about the automative industry, and preferably you should have internships or other work experience in the automotive industry on your record. From what I have heard, you need at least a 2.0 GPA (in Germany) and a good grade in Maths. Also, some people mentioned that Berylls doesn't prefer candidates with a degree from a university of applied sciences (FH)) and candidates coming from Big4, but I don't know if this is always the case.
If you find any more info, feel free to share it with me, as well ;)