Hello,
Could you please send us the photo of your car's dashboard? then we can help you check if this unit can fit your car.
we are sorry we don't have installation video for this unit at present but we have wiring diagram for it. Don't worry, most cables just plug and play.
Yes, you can ask for refund if it doesn't fit, but we will help you check if this unit can fit your car before shipping.
This unit has bluetooth function and also has gps function and its bluetooth can connect to your galaxy s4, but your original car's cd changer will not work after this unit's installation.
Your original GPS box will not work but this unit has built-in gps and we will provide gps antenna to you.
Yes, the DBD computer and all the BMW diagnostic and features will work.
Sorry, you have to pay for the shipping cost and we are located in China.
By
Seicane