Thanks Pete
That's probably a reasonable system too, but sacrificing the CD player could be a down side.
As far as "audio quality" is concerned, you're probably starting with a .mp3 music track, which by its very nature is distorted, and reproducing the sounds in a vehicle; a steel box which vibrates and sometimes rattles; a finely tuned audio theatre it isn't. And no amount of oxygen free cabling, 1 farad capacitors, fancy loudspeakers and super-bass amplifier systems are going to be able to repair that.
As I've already said in an earlier post, the device I've recommended is NOT an FM transmitter which is prone to all sorts of interference, but a device which actually connects into the aerial line. The audio reproduction while using the MkI ear'ole is no different to any other FM radio station output. I've no doubt that if you turned up with an audio spectrum analyser you could find a difference in reproduction.