Our Cmax has OE front and rear sensors which seam to give good coverage, are reliable and work well when parking. However, when stationary at a junction or in a que of traffic, if a bus/lorry/motorbike goes past, or its raining the front one keeps going off and its really quite loud too! On the other hand, the rear sensor is so quiet you have to turn the radio down in order to hear it! Why the need for the volume to be reduced in reverse?? :roll: