Though I did get a yes to the question of retro-installing the rear sunshade from my worthless dealer, it was confirmed by the people in SC. during the M5 performance program. I have the parts on order and will have Rolling Thunder(custom high end auto stereo) do the install. Though the rear shouldn't be a problem(I hope), it is my understanding from previous postings on this site that the rear doors with the covered sills become too thick for the mouldings that accept the manual side screens, thus, the omission of the option. Rol Thun and I will have to cross that bridge soon. I think the parts cost was around $1200 for the three sides of the car. Luckily I got a discount(from another dealership). I have this option on my 540/6 and I miss it on the M. I'll post the outcome.