OK i think you may have the BITRATE confused with VOLUME....all the songs you find in limewire are basecley the same volume so you dont need to worry about that at all. but there are many differant bit rates ,bitrates are directley linked to sound qualety.

for the best sound qualety onley download songs that have a bitrate of 192 or more. 192 is OK but 224 , 256 and 320 are the best.

now what you probobley did is burn and mp3 CD and not a normal audio CD , in wich case the CD you made will refuse to play on any player that dosent support MP3 CDs eg your car.

your one sterio probobly supports mp3 cds and thats why it plays on that and nothing els.

if you DID make an audio CD you may have used a CD-RW or some off brand of blank CD-R . in this case , some players cant read CD-RWs or are pickey about CD-Rs.