1) I have the Sirius in my 2004 E60. I had the dealer install, so I'll have to look to see which connector was used for Sirius. Are you thinking of doing this yourself? While you may be able to buy a module and plug it in, the dealer still has to update your iDrive software to work w/ Sirius. Unfortunately, no simple plug and play on this option.
2) $250 to program it for BT? It was my understanding that 2005's came BT ready and all you had to do was pair your phone with it. On older 2004's there is a software update required, where I might understand a charge, but even that is debatable. As long as your system isset up for BT, and it should be, go to this link for more on pairing your BT phone. http://forums.e60.net/index.php?showtopic=5103