When I bought my 2005 4.4 X5 It was suppose to come with dimming side mirrors, but only came with a dimming rear view mirror. I want to add the dimming side mirrors. Does anyone know if I need to run any wiring to the mirrors, or is the wiring already there and I just need to replace the mirrors? The dealer told me not to bother since it would cost around $2000 to retrofit the 2 side mirrors. Does that sound right?