I would contact Vines Auto
http://www.vinesauto.com/ and tell him what you're planning on doing. If he has a 535iM that he's parting out at the moment, he can piece together what you'll need. I had him do this for me when I was thinking about converting my 525i to stick, and it came to a little over 1k$ for everthing- pedals, clutch, clutch hydraulics, transmission, driveshaft, etc.