Bad physics, wrong (fantasy?) specs and weights, bad 3D models, weird shaders (with bad normals on some models, namely the Camry), severe inconsistencies (for instance: completely black windows on the Camry and then inside they are completely translucide to the point of appearing to have no glass at all), some cars don't have external sounds (!?), wrong descriptions on some cars, poor textures on some interiors, etc.
The mod does have some potential. If done right, it could be one of the most enjoyable mods for AC. As it stands, though, it needs A LOT of work. I do hope you keep on improving the mod. Ask other people's help if you need. We are a tight, cohesive community after all. Cheers!