as for what DJM means, I'm not sure as I think it's just a prefix, it has no meaning for it

In game they don't really have much of a difference but there's a few visual differences (and sound differences which I have yet to add) between the three as they're different types of V Sets that were made over the course of their production that still run today. DIM is the oldest, DJM being the following batch and DKM being the newest type. Hope that clears it up a bit!

Hi whats DJM? i noticed you have three types thanks.

Hi, I plan on making a transport project series similar to Blue Thunder, I'm wondering if you're okay with me reskinning your assets. - AWT