u/Electronic-Juice8792

Hello guys, so recently I got an error in my car oxygen sensor after catalytic converter, I went to my local garage and the guy had an unused sensor there from an older f10 he changed, but the error persists he says I need to buy a new sensor and that he recommends oem sensor which is around £300, but I found a Bosch sensor for £130 at Napa store near me, so my question is do I really need an oem sensor and pay more or should Bosch do the trick and fix the error? Thank you

Hello, recently I bought an F10 520D 2015 B47 engine, and I want to ask if anyone knows if this engine sound is normal it’s like a metalic noise, car drives fine otherwise, also there is a whistling noise when driving on the motorway at higher speeds but the noise completely fades when driving behind a truck, some friends told me it’s wind related but I’m not sure, thank you