AlexusAnja

This link also has the part numbers needed. Not sure if Lexus even carries this still.

https://www.clublexus.com/forums/ls4...004-ls430.html

Lexcel

Actually this is not true. It's model/year dependent. On RX330 there are no AM/SAT buttons and the RX300 ran through 2006... Just an AM button on these cars. On the RX350 in 2007 (as Sirius radio gained popularity) Lexus added the AM/SAT button. So on 2006 RX330 there is only an AM button, but on 2007 and newer (when the RX300 became the RX350) the AM/SAT button is in it's place as one button.

I concur with a couple other posters here that having the AM/SAT button just means your dash radio is satellite capable, you still have to add the tiny box in the back of the stereo. This came as a huge shock to me when I bought the '07 RX350 and the Sirius wasn't onboard (oddly on a 2006 Acura TL it was ready to go, just a phone call to Sirius and it worked). Even the hapless Lexus salesman told me to have it done at a 3rd party stereo shop because the service dept will gouge you on the install. I even got them to cover the install and part cost as part of the deal buying the car because they could see how I didn't like the vehicle wasn't truly "satellite ready", when the Acura I bought from them a year prior was.
Expect to pay around $300 including all parts to have a stereo shop do it.
If you do it yourself, the units are cheap (under $70) and a simple Sirius antenna apparatus is under $20 on Amazon.