to the system. Listened to a 2009 A4 with B&O and it sounds far better than my S5 did when I picked it up. Bass is linear and seamless with an authoritive bottom-end. Doesn't help that they also have rear foglights standard. </rant>

There has to be a way to tweak this amp. The output of my factory sub wasn't even on the same level as the new A4. It sounds so good, there is no need to upgrade the sub.