Yeah, I'd say if you want a changer, make sure it supports MP3's. Six MP3 packed CD's is a LOT of music!

I personally didn't bother - I replaced the failed CD changer (it failed within 30 days of purchase) with a cubby hole and replaced my head unit with a nice aftermarket MP3/CD player. Aftermarket electronics are MUCH better than Isuzu's stock junk, IMO (and my new VW isn't much better). I try to avoid 6 disk changers that fit into a single DIN opening like the one that comes with our VX because they tend to break and get jammed more often than larger, trunk mounted units.