Q5 B&O upgrade help

[Nashy]

Hi,

I’ve just bought a 2013 3.0 Q5 line plus which has quite a few upgrades including the B&O sound system.

As per a million other online posts, the sound quality is not what i expected and I’m looking to upgrade it if possible.

I don’t want to go mad, or have a huge sub in the boot, just improve the quality a bit especially the bass.

Lots of varying opinion, ideally I’d like the minimum fuss.

Has anyone changed their sub with good results or is there any advice on this please ?

Thanks in advance.