One thing I would say though is that with my exhaust system, any radio/CD is almost useless when driving!
O, I don't know that I would agree with that.
IMHO if you have a decent system using either the OEM amplifiers or aftermarket set up you can listen, top don easily. I will say that it's a noisy ride though. I have the original amplifier system with an Alpine head unit and I can hear fairly well.
It can also help if you roll up the windows on the highway with the top down (stowed?). Also, the type of music you listen to is imortant, classical music might be a waste of time and actually is not worth listening to in a car unless its a quiet car with a real nice system, but top 40 and rock n roll should e no problem.