Oh, I was also going to suggest 7zip as soon as I read the mention of WinZip. I didn't know about PeaZip, though. I'm reading now and it's interesting, as it has a dedicated GUI, if I understood correctly, even in GNU/Linux.
About the file name containing more than the car ID, my personal vote would be that, if the name is longer than four characters, the best choice is that the four first be the car ID instead of the four last. I'd say the ID should be case-insensitive, but it should default to uppercase. That is, programs recognising the ID should treat both cases as the same, but people creating the package should try to use all caps for the ID. The rest of the file name is OK. I could suggest avoiding spaces. Anyway, all that is my preference. It doesn't have to be that way.