Will a 2009 Q5 B&O hifi fit into a 2018 S4?

[wordsman]

My cousin has a 2009 Q5 3.2, with Bang & Olufsen that he hardly listens to. I have a 2018 S4 Avant with the standard hifi and was wondering if it's worth making him an offer.

Would the B&O transfer to the S4? And how much do you think it would be worth?

THanks