I'm not sure about those things that broadcasts to your FM band.

I live in Los Angeles.
There are a billion FM stations.
The iPod FM transmitter thingie is worthless.
All the frequencies it can transmit on already have a station.

It did work great out in the middle of nowhere though.
I suspect the XM things must have the same problem in a big city.

But out 2006 HCH2s have a minijack so we don't have to use the FM transmitter feature.

Need fewer troops to support.
Drive a hybrid.
Best tank 71.65 MPG.

Before this car I spent two years learning hypermiling on my 2004 HCH1.