Sorry can't remember the part numbers from BMW, but they are sold in pairs, fronts and rears. For some reason the rears are more expensive???? When you go to order them, make sure you you tell lthem you want them fore the premium system.
No additional wiring required, but truth be told, I had it done professionally. They had to play a little with the passanger front door fitting, but not difficult I was told.
In terms of how they look, they look just like the door trims in the brochure, a liitle speaker cover in the door grabs.
These are made as a straight swap, right size etc.