I can't find the solution to this but for some reason there are these pink circle things inside of my cars and some of the parts are taken out and automatically renamed. 

I can't delete anything and so now I can't finish my pack 

 

Those pink circles look like dummies, they're supposed to be there.

The car isn't missing any parts, the livery texture is transparent. Go to where the textures are and look for police_sign_1 or something like that and replace it with a texture that isn't transparent. Then re-import the car.

You didn't import the model right. It the import screen should look like this: 

 

 

You need to check "sliced model" and "collision".

Those pink circles look like dummies, they're supposed to be there.

The car isn't missing any parts, the livery texture is transparent. Go to where the textures are and look for police_sign_1 or something like that and replace it with a texture that isn't transparent. Then re-import the car.

 

 

You didn't import the model right. It the import screen should look like this: 

 

 

You need to check "sliced model" and "collision".

Thanks. Your help solved my problem!