no, it's not aftermarket, although you can add it to your bimmer. check
out the forums at bimmerfest.com. there's all kinds of info there on do
it yourself projects. they helped me install an oem navigation setup in
my '05 325i. I got it off the lot, and it didn't have GPS, but it had
every other option I wanted, so i took it anyway. I found all the parts
for the nav system and put it in myself with help from those forums.

as for the bluetooth, i know it was installed standard in all 05 3
Series that had BMW Assist. My car has Assist, so I got bluetooth. To be
honest, I made sure i had Assist because I wanted bluetooth. Only to
find out later the Nokia 6230b won't work with it.

if you need more info on installing bluetooth, let me know. I've never
done it, but i may be able to help. i did just rip my car apart to
install navigation. (my family still thinks i'm crazy for tearing into a
brand new 40k car)