Well, looking at the zmod shots it looks like the normals on the side of the nose and sidepod are turned slightly up and down on the top and bottom respectively. Essentially it means that from a lighting standpoint the what should be flat parts are considered as round.
Here goes my little rant on normals, not just to Diego but 95% of the carshapers out there
Mathematically speaking, the normal vector at any point on a plane is perpendicular to the plane. Of course in ZM, we don't have normals on the faces, we have them at the corners (actually impossible). So essentially we have to consider the normal at the edge of a flat part to still be perpendicular to it, and not consider the round when calculating normals.
The way I build cars is to build the flat parts first, calculate the normals, then build the fillets and rounds, then calculate those, leaving alone the flat parts. And having the normals auto-calculate on is a mortal sin
Here's a little example of what I mean (no asking me to release this car). Notice that on the flat parts of the sidepod, the normals are all parallel.
The downside is that it doesn't look all that great ingame. The sidepod is a bit too dark and doesn't pick up relflections the way it should. That said, I'm still doing it this way, as I think it's the "correct" way to model the car. Some people might disagree with me if they like to have a little bit of reflection on the side of the car.