First you need the M5 mirrors that are equiped with the autofold feature. I bought mine from bavarian-motorwerks on ebay. There are many other companies that sell similiar mirrors or you can purchase the OEM mirrors from a BMW dealership, but you will pay around $1,400.00.
Link below, I paid $235.00 plus $40.00 shipping. http://cgi.ebay.com/ebaymotors/ws/eB...category=33649