If you are wondering how much you can fit in an S6...

A6 All/ S6 All
#1

You can take a whole home theater system:

https://i.imgur.com/kJDOBA8.jpg

2x floorstanding speakers
center speaker
subwoofer
receiver
power filter (not pictured)
cables/controllers/HTPC boxes

and still have the front passenger seat free ;D ;D