Sites to download Creo Parts and Assemblies

Hello All,

I was just wondering where people go to download part files. I find it really useful for proprietary parts and for complex models a good way to see how complex parts are built up.

I have found GrabCAD, but this covers all CAD systems and doesn't tell me if the files have been created on a professional Creo license or a student copy. I need the files to be part files, not some export types that can;t easily be modified.

For example yesterday I needed a tension spring just to indicate where it would go in an assembly, I found a nice one on GrabCAD, which allowed me to modify it enough to look like I wanted. 

Gavin