Roy, Subaru doesn't mention whether the base stereo is six-disc or not. I'm inclined to think not, because a) they'd have made a point of mentioning it, and b) the new MediaHub system allows the connection of a portable music player, which I suspect most buyers of these cars might expect, rather than a CD-changer.
To actually answer your question: I think the CD-changer is gone, but Bluetooth is standard in both the WRX and STI.