I bought the audio adapter and the Monster RadioPlay 300 FM transmitter a few days ago for my Pearl 8100, and I could not be any more satisfied!

I get perfect sounding audio on numerous stations from the FM transmitter to my car stereo (I live about 10-15 mins away from downtown ATL).

If you don't have a cassette player in your car and want to play your music in the car I HIGHLY suggest this combo. Although FM transmitters are known not to work very well in big cities, I suggest you atleast try the Monster RadioPlay 300. It can be found on eBay for under $20.