I recently (2 days ago) had the Lexus dealer installed Sirius option installed in a new 2005 LS430. Reason for going with Sirius vs. XM was availability of NPR and some other programming differences. It was first installed about a month ago in a car I then had to reject due to paint problems. It was then I discovered that the Sirius install uses an inside head unit, and contrary to a previous posting, does not fit under the mirror, but rather adjacent and down from the rain sensor on the passenger side. My wife was *not* happy. However, the wiring harness for this one was defunct so I never was able to use it. After about a month they delivered the replacement which I took delivery of two days ago. I spoke with the installer about the placement of the head unit. We negotiated a position (different from the official Lexus/Sirius install instructions) on the driver side of the mirror. It won't fit under the mirror because they (Sirius) made the head unit to high -- it may fit under some of the SUV's but not the LS. Engineering mistake #1. Also, the "tail" that connects the wire to the head unit (the one that attaches to the windshiedl) prevents the unit from being installed flush to the bezel (by about 3/8"). So I allowed the installer to create a notch so that it would fit more snuggly and save me 3/8" visibility. Engineering mistake #2. I didn't get any information (e.g. users guide) with the unit. Called Sirius (after looking at the web site activation) and asked if there were any "free offers" or discounts. Turns out, after the service person took my Sirius ID number that you can get 3 months free (and apparently waive the activation fee as well) with any plan (took the one-year plan) for any "Toyota car" (that's apparently how they view a Lexus at Sirius). OK, now I'm connected. Turned it on. Worked. However, rather than providing a "Next" button for storing programming, one has to do the same things as with FM (ie. FM1, FM2) which means you have three SAT1, SAT2, SAT3 and each time you change you end up changing stations to the previous default. Not the smoothest. Engineering mistake #3. The information display (for the song/artist) is limited in each case to *ten* characters. I listen to classical so the composer is "Alexander " who? The song title is "The tale of" ? Obviously someone messed up here as the Lexus display has room for at least 40 chararcters. Engineering mistake #4. On the road, the system loses signal if one's driving along a tree-lined street (lots of them in Atlanta), or if there are storm clouds (lots of these in Jul/Aug in Atlanta). Apparently XM overcomes these problems in major metro areas by providing a substitute RF signal from land-based antennae. Finally, for Atlantan's the traffic reports are combined with those of Boston's. You turn it on, and you're not sure if you're hearing Boston's weather or yours. Have to listen for a complete cycle. Not too smart.
Bottom line: Think twice about Sirius if a). you're getting an LS, B). you don't like truncated info on your DVD display, c). you don't want part of your view obstructed by the head unit, and/or d). you'd prefer traffic/weather information that's specific for your city.
Picture of non-stand installed head unit attached.