I have this FM Transmitter here:
http://mediaplayers.co.nz/index.php?...d&productId=14.
It works fine on my car stereo. The sound is good enough. I haven't tried the FM tuner from my mpx player through to that FM transmitter though.
I do notice that in some areas it gets abit 'cracky' and I get some interference and static noise. But then it goes away. My FM transmitter has four different FM stations to turn it too.
What FM range is your transmitter transmitting it in? Mine is in the 88.x range. Some are in the 100.x range.