I took a look at the content requirements for this particular product.  First, it is 5 years old with no upgrade mentioned in the Editorial section.  Second, it was created initially for PoserProPack, no testing in DAZStudio whatsoever.  Third, it was developed as conforming clothes. 

To properly conform clothing to character, you must pose the model first, then add your clothing to the scene and conform.  You should see very little pokethrough, if at all, if the costume was created correctly.  As was mentioned, making body parts invisible offsets this problem. 

The extrusions may be related to whether you are using OpenGL or SreeD.  Switch between them and note any improvement.