I don't know too much about car audio, but I havn't heard of any of them support FLAC or other similar lossless formats. Who knows, some fancy cars may do. You might try wave, which is also lossless and as good as or better than any other format. You can try mp3 at home and see if you hear a difference between the original CD and the converted mp3. If you hear no difference, then that's the answer for you. However, if you ever want to upgrade your gears in the future, flac is definitely audible better than MP3. If you have a lot of CD to convert, I would choose flac over mp3 for "future-proof". I use dbpoweramp and jriver. It seems to me jriver (fee) and foobar (free) are two leading ones in the PC world. You can't go wrong with either. Since jriver requires a fee for a version upgrade, I'd recommend you try foobar first to see if you like it. Jriver offers free trial you can download and try before buy.