Ah right. Mediaplayer is a one-stop-
shop for turning a CD into a compressed audio file capable of being played by mp3/wma compatible units? Yup?
Well WMA as a rule is a superior alternative to MP3 at low bitrates. An example would be the fact that an MP3 under 128Kbps sounds shoddy.. Cymbal crashes and higher-freq. notes sound watery and crackly. I'm sure you know the kinda effect I mean. But one of WMAs "selling points" is the fact it works to negate negative effects on highly compressed audio files. My opinion on WMA is that it sounds cack at high and low compression... so I'd rather get less songs on one disc and enjoy 192Kbps or better bitrates.
Basically, if you wanted to make the most of your in-car audio equipment and not lose too much sound quality in the process of encoding your CDs, my advice would be to google Audiograbber. Ensure you download LAME.dll from the website as well. (LAME is an open-source high-end audio compression codec... basically, its fantastic.)
Audiograbber will name each and every track for you, including track number, year of release and album name. It'll then rip them to your PC in a choice of bitrates. (The higher the bitrate, the larger the file but the better the quality.. or more accurately, the nearer CD quality it is.)
Once you've got yourself a handful of albums encoded, you can then drop them on CD/DVD ready for playing. Any CD burning software will facilitate this. Use your favourite to burn a Data CD. If your headunit supports folders, try arrange your music accordingly. It's easier to navigate for a start.
Once you've got your newly burned CD, choc full of MP3s.. just play and enjoy.
Plenty of websites exist that compare WMA to MP3 but I'm sure most people will agree that at higher bitrates, MP3 is the superior of the two.
Hope that helps.