The graphical side of it is not as important for me at this time. If it's functional and it's visible, it's fine. But with the particle systems the work involved in just making it look so much better than the first draft implementation was miniscule, so I spent an hour on it.
More importantly however, technically I had to consolidate a bit. It's so easy for the code to run away from you if you're not carefull. Sloppy implementation up-front will make for big headaches later on in life. That's kinda common knowledge. The problem with prototyping though is that you tend to rush through things with your mind on the game play design and not so much on the implementation design. Because the purpose is primarily to test the game play, this isn't a problem per-se. However once the game play is confirmed and the idea is not binned, you have to go back and refactor and revise that implementation.
So after some structural changes, some new additions to the XML pipeline and three re-works of the smoke and new dust textures, this is the result. The dust trail specially adds a lot of base for me. It makes the vehicles have substance. But anyway, I hope you like!