Could you give some simple renders, just the normals (no diffuse), no white outlines. Just simple black wireframe on a clay render? I think I see a few really simple ways to save a lot of polygons, but I can't quite focus with the complex rendering style and the triangulation.
Realy nice work, i agree with must of what the others have said. I would like to add that the field of view is a bit to high for my taste, the perspective gets distorted. I like the mud you have added nice tough, but it might be to noisy on the tires. Also would be nice to see a wireframe of the humvee :)