Great job bringing a cool unified whole out of a mix of parts.
To be honest, except for the decal, nothing about it says "Necromunda" or the 40k universe to me. However, I think it's a brilliantly executed model that would be a fantastic for any of the post-apoc vehicle games I've played. Wastelands, Nuclear Renaissance, etc....
Nice job on the EM4/Grenadier post apoc figs also. I have the same figs, but yours are much better painted.