This is all you need. Everyone else marks it up. I did this on my 4 series. It was a bitch to install. That’s because I’m a fool and didn’t watch the tutorials before starting. Hahaha. But once I got the tools I needed it was relatively easy. The only objectively tricking thing is fitting this new box in the space with the head unit. Takes a few tries.
It works perfectly. I didn’t like however that it piped audio through aux. I like my audio high quality.
https://www.amazon.com/dp/B084M1M4P9...CVAHRD9YTZ0DB0