Am looking at connecting my mp3 via the CD changer port on the back of my factory fitted Grundig stereo in my 1999 Brava. I've read the other threads on here about doing it just wondering what the sound quality is like or would it be better to get a new stereo with a built in aux out port on the facia.

New stereo.
A good adapter will be around £30? a half decent stereo that is far more up to date with higher powered outputs for your speakers will be maybe £60 ish, probably pick one up second hand these days for £35-50.
Paul

cheers may go for the new stereo option.