Factory Stereo Selection Help?

Hi - I'm planning to buy a 2009 car in the 40-55k range, and am mainly looking at Lexus, Infiniti, Audi, BMW, Acura.  I'm searching everywhere for comparisons of the high-end factory stereo systems installed in these cars but am coming up empty.  Since many of the 2009 cars haven't been announced yet, 2008 comparisons would be fine too.  Features I'm most interested in are:

1) Satellite radio.  Sirius, NOT XM
2) High quality iPod control
3) Touch-navigation

I really appreciate any guidance you can provide, including websites that contain these comparisons or even your own personal recommendations.

Thank you VERY much for your help.

Greg in NJ