I had read some time ago that for getting best compression in WinRAR command line switch(parameters) should be used. They provide maximum control of the settings and provide maximum compression ratio. But I never took the pain of finding out the actual commands.

The best compression program is not KGB Archiver, it is WinRK(i forgot the actual name. It is something like that). It has been developed by a single person, not a team. He is a Kiwi. The program is not free, it is Shareware.

KGB is the best free compression program.