[nodek]

I have a 2014 BMW 320I (F30), the shock absorbers on it have never been changed before. Went to the mechanic and was told the rear ones need to be changed (the ride is extremely bumpy now).. I trying to order them online but need some help..
1.Does anyone know any online website i can get the genuine shock absorbers to buy?
2. Do i need to order the entire suspension system r just the rear absorbers only?
3. I have seen a lot of website selling the Bilstein B6 for the F30, does it fit without any modification and is it equivalent or better than the stock absorbers?

Need some help pls, first time owning a BMW...