My wife just purchased the new 2008 Highlander Limited yesterday, and it came with a Sirius-ready premium JBL sound system.
Apparently, enabling Sirius requires the installation of an OEM kit including an antenna and Sirius tuner. I've searched around a little bit for this online, and my best guess so far is that it's the TOYSIR2 part that does the same thing for a number of 07 Toyotas.
Does anyone have any experience installing this kit in a Highlander or other model? Looks like the price is around $300 -- I'm wondering if this is something I can install myself. I've installed Sirius in a number of other vehicles, and actually replaced the factory Sirius tuner in my Dodge with an aftermarket model, keeping the stock antenna.