I got very annoyed with the volume going up on the Aura HU. It never seemed to put it down again and I was forever turning it down manually.
I put in a Pioneer P9800BT (with extra amp and 12" sub). The manual says it has the capability but I haven't bothered to check - I just have it loud all the time. It makes you jump when you get back in the next day and forget how loud it was.