Be wary of buying a Chinese one....
I have one (it came with the car) and the bottom of the head unit isn’t curved to fit the e53. It is listed as e53 and all 5 series compatible but I think the normal 5 series range use a different figment.
The screen is facing too far upward so you can’t really see what’s going on, but it has all the sat nav, mp3, Bluetooth, aux, touch screen and looks fairly standard and would fit well in a standard 5 series, so it’s worth double checking if I’m not mistaken.
I’ll try and get some pics when I get home from work.
i will change mine at some point, but it plays music, the wife is happy and I have more pressing matters 😂