general problems of the 2006 Mercedes Benz E320

I changed the low beam halogen bulbs in my headlights when I discovered that the wire leads to the bulb had lost nearly all of their insulation, exposing bare wire. The insulation flakes were sitting in the bottom of the capsule that contains the light assembly, which is normally closed, accessed by a removable "door". Both headlights had this same issue. This is an obvious sparking/fire danger, so I applied electrical tape over the wires. Had I not changed the bulbs [they lose brightness over the years], I would have been unaware of this danger. I am concerned that this same wire insulation has been used throughout the vehicle. I am amazed that mercedes has not issued a recall on this. I purchased this car new in 2007.