When sub-materialing something with a pattern/texture/whatever onto most surfaces of almost every model they are very stretched and sometimes distorted, so I can only use solid colours without making the models look bad. That's the only problem I've seen about these props, but it's just this one thing I've noticed that prevents me from really doing much with them.

Just discovered the Pullman Standard cars have their couplers flipped on one end.

Unusable? I can't seem to find them and gmod is saying errors

The terrible UVs make trying to texture the M7 impossible