I’ve just bought an A4 Cabriolet 2.0 TDi 140 ‘57 and it’s non S-line, and as basic as it gets, no cruise control etc. I’m new to Audi and so don’t have a lot of knowledge. Can I upgrade the standard head unit easily, straight swap, for even another Audi head unit that might have hands free ? Doesn’t need Sat Nav just looking for a calling option at minimum ?