Yes. MP3 compatible headunits play CD's burned as data cds in raw .mp3 format. It will preserve your directory structure, but be sure to get one that allows directory browsing and displaying of directory names. Some cheap ones display stuff like "Folder 1", "Folder 2", etc. It's very... non-helpful.
I've never seen an HU that can play MP3s in DVD format. I'm sure it's either in production or out there and really expensive, though.