Zip has many advantages over InstallShield EXE installers, it cannot be contaminated by a virus (Poser files), you can install in any folder what you want, you can extract only one file that you want and you can view a file inside the zip. I use WinRar and have associated *.pp2, *.3ds, *.obj and *.dxf with my PropViewer (free stuff). When I open a zip with WinRar, I can click on the pp2 or obj and I see how the model is, if I click on a jpg it open Paint Shop and I can see how the texture is, all without extracting or installing, a very handy tool for managing large collections of 3d models.

Stupidity also evolves!