This is amazing Ezra, well done! Just one thing to point out though. For the storage compartments on the body, I would putting stripping to give the impression of dividers. In your rendition, the side just looks like a huge roll-up door. Check this link if you don't understand, and look at what Zak did with his. Once you do that, it's perfect!
Wow, what a beautiful truck! As Impels go, this is one of the best. I love your pump panel, compartments, hosebed, and frontal lighting design. And you even outfitted it with chevrons! I hope those pesky chevrons didn't give you any trouble. It's a beautiful engine, and I might just be back later to add more to this comment!