I bought an already built SE and had the dealer fit front and rear parking sensors. Externally they are identical to factory fitted. A SEL was being collected at the same time I collected my SE so I could compare them. I only get an audible warning, they are not connected to the visual display, There are 2 slightly different tones and the sound seems to come from different places, ie the rear sensor beep from behind me. They can be switched off as an additional switch was installed My driveway has a lot of vegetation so they do get quite hysterical. They carry on warning me whether of not the car is in gear. If I open the door with the engine still running whist the sensors are operating the car has a meltdown. I am happier having them than not. I have never got on with reversing cameras but wanted the beeps. I think it was a little dearer than as a factory fit option.