So folks i figured it out on my car. for anyone interested in installing a T1819 (2012 base) radio in a 2006.5 minus XB i did it and my aux in is now working. to summarize things you need:

Head unit
3 oem harness that come with it 20+8 adapter, HD antenna, and speaker
BT mic from scion IQ part #

if you have all the above it will work with BT and HD radio now for the 06.5 people with Aux in you need more stuff.

you will need a 2.7k Ohm resistor i bought mine from radio shack in a giant misc pack that cost $15 so i recommend just buying them online. also a small tube of silicone or hot glue

once you have those on the 20pin harness from the car i put the resistor in pin 19 and 18 (red/silver = 19 and 18 is unoccupied) this is a PITA but shove the resistor in port 19 first as far as it will go and then push it all the way through 18 and bend it over the top of the plastic clip so it is held in place.

turn your radio on make sure the aux now works turn it off put a dab of hot glue or silicone on it to hold it in place.

I could add photos but for the most part i think it's pretty straight forward now.

 

Do you have any pics of install?

 

i do somewhere they are posted to an xb specific forum already. is there something you need to see?

 

Just curious to see how it came out.

 

How about a link to the forum/pics??

 

http://www.clubxb.com/forums/showthread.php?p=1021970. ll post a link but not sure if its allowed so if not please remove.