I want to get either XM or Sirius radio, but I don't want to use a FM modulator or transmitter. Direct connection would sound the best. Is there any way i can do this even though i have the 6 disc in dash cd changer? I also have an Ipod i'd like to hook up. If so how much would it cost me to do this? If I can't do it how good or bad does it sound with the transmitter or modulator? Thanks.