I was pleased to learn a few years ago that plain ol data cds work fine for audio projects and they are cheaper and of better quality. But I've been wondering about audiobooks. I have a subscription to audible.com and it takes like 10-15 cds for a book, so why can't i throw them on one of those dvd discs? Are they really 4-7 gb or is that of compressed video data, will it play on a car cd player that plays cd-rs? I thougth I would ask before trying as they are a bit expensive.