I have a 2007 Limited V8 with the factory nav system, and had to buy the following to get XM (about a year ago):
86180-0W030 RCEIVR, XM SDAR ($218.90)
PT546-89060 FITKIT, XM, 4RUNR ($113.30)
I bought these at Liberty Toyota in Colorado Springs, and they charged me $150 labor for the install...