Hey guys just had a sensor go bad that caused a PDC error, easy to find which sensor is bad (search) and everything i read says bumper needs to come off, not true i reached in and took about 5 minutes if fidgeting with one hand and got the sensor swapped out, the wires are long enough and give you plenty of room. This was rear side, 06 m5. not sure about fronts. Simple push/pull clips hold them 2 tabs (not twist) just unhook 2 clips and push sensor from the other side into the bumper.