(imported comment written by SystemAdmin)
I wouldn’t use WinRAR since it is not freeware. I personally use 7za, which is the command line version of 7zip. I prefetch it to the machine and add it as a “utility” so it never has to be downloaded again. The command line was a little tricky, so here is an example:
prefetch 7za.exe sha1:4154dda4a1e2a5ed14303dc3d36f448953ff6d33 size:536064 http://server.domain.com/bigfix/7za.exe
waithidden "__Download/7za.exe" x __Download/archive.7z -o__Download
That command line will work with any format that 7z and Zip formats, but I prefer to use 7z as it compresses a bit better. The files will be extracted into the “__Download” folder, so you can then you can run an installer or do whatever you want to do with them.