How do I use these models?

     -To use these models, go to File > Append (SHIFT + F1) and choose the appropriately named object group in the "Group" folder of the .blend file. 

What about materials?

     -To use the included materials, repeat the process shown above, though, choose the appropriate materials in the "Materials" folder of the .blend file.

Are these render ready?

     -Yes! Just add the models and apply the materials and you are set! Though, please note, that you may need to adjust the subdivision level of the objects that best fits your needs. It's also recommended that if you're using the low-poly models to leave them with smooth shading.

---Technical information---

Sub-division 1 polycounts:

     -Combined total: 22,262 verts. 19,525 faces.

No Sub-division polycounts:

     -Combined total: 9682 verts. 6,626 faces.

--Materials--

     -Chrome

     -Steel