For starters, there will be no official PWF Truck Viewer. They will, however, post the 3D models after the mod is released. Whether they will be .3ds files or .max files, they have not specified. As long as they can be converted to .3ds files, they will be viewable in Z-Mod. If the models convert with no problem to .x file format, then they can be loaded in the latest N2003 Car Viewer (at The US Pits).

Also, the Chevy truck render you guys have been seeing is the Thunder model tweaked and remapped and shoehorned to fit to the PWF template. This variant was originally posted in .max format, and had a very high detail chassis added to it. Someone exported it to .3ds format and sent it to me. I attempted to convert it to .x format (for loading into the Car Viewer), but the conversion failed. I suspect that the sheer amount of extra parts on the model were too much for the converter to handle. Maybe if the extra parts were removed and just reduced to the bare essentials (shell, tires, glass, etc), a conversion would work. I don't know anything about modeling, so someone else is going to have to do this. The only other option is to wait for the authentic PWF models.

Hope this clears things up. If you have any questions, mail me and if I know the answer, I'll amend this text.