In bmw x3 stock sound system is crap. I already replaced all speakers and on an easter sunday I decided to install amp. I already had it from previous car with all cables and other stuff I needed.
There are several options where you wanna install it. I decided to install in it trunks floor.
It is very easy to connect power cables because BMW’s are having battery in a trunk.
You need just to install cables for signal cables like remote, 3 pair inputs RCA and I also install cables for rear camera.
Dash, cables every where 🙂
And finally 12 inch sub
I already installed 2 din radio in my x3. Sound is so much better now. I can finally enjoy it 🙂