I've had no problems with my stubby reception living in London, and only rarely have I had to retune elsewhere in the country. I've never had problem with the TMC traffic updates on the sat nav either, even in Europe.
IIRC the external antenna is there for AM and to act as a backup for that in the rear bumper when reception is poor.
As for listening to the radio or hooning tunes when I'm having fun....I prefer not to have any musical accompanyment to the sound of :evil: