[quarky42]

There is more than just a registry patch going on here to do this. There is a service running in the background that resets your ICS back to Sprint's default. The cab disables the service and if memory serves me, it replaces the program too in addition to the registry changes that are required to enable to ICS.

I too would like to know what is different about the three versions, if anything. You can't go by size because one could be compressed and the other not.