What the folks at BB were talking about was the Pioneer IP-BUS port. And no, Scion radios do NOT have IP-BUS ports.
The hookups on the back of the Scion factory CD radios are completely different from Pioneer's, and they use a different "language" code to communicate the channel names, song titles, etc. to the head unit.
It is POSSIBLE to use a Pioneer Sat tuner with the factory radio. You will need SoundGate's PIOTOY1 CD changer adapter ($100), and since the latest Toyota radios use a newer CD changer plug type, you'll need an adapter from Toyota to adapt the older Toyota plug type to the newer. This part is about $20.
BUT!!! You probably won't want to do it. Read on for issues...
1) You only get Channel numbers. No Channel Names, no Titles, no Category sorts. Just a number.
2) Because it emulates a CD changer to feed the signals, there are no presets. Have to manually tune to each channel desired.
3) The Up/Down buttons won't scroll through the channels. You have to push for each channel change, one by one. Want to listen to XM Comedy? Better not be driving, that's a whole lot of pushes....
4) No way to display Radio ID.
5) Output from the Pioneer Sat tuner IP Bus is lower than the factory Sat tuner. Takes about 10 more in volume (30 on Sat sounds like 20 on CD).
But here's the kicker...
6) Due to a glitch in the CD changer emulation, if you turn the car off for a brief period (like getting gas), the unit will try to search for the last Channel number tuned as a CD number when restarted. For example, BPM shows up as CD81. Because the CD changers don't have that capacity, it can't find it, gets confused and locks up. That's right, dead. The ONLY way it worked in my car was to remember to tune the XM unit back to Preview channel 1, which to the CD changer emulation looks like a normal CD1, Track1 code. If I forgot, I had to either disconnect the battery or pull the radio fuse to clear the XM unit.
Doesn't that sound like a dream come true? Geez.......a 3 day nightmare.
Pulled the factory unit, installed a Pioneer 6500, all is good.
Any questions, I'll try to answer them....
ps...SoundGate is working on a conversion box from Scion to Pioneer specifically for the XM tuners, but it's about 6 months away.