Should Israel worry about Iran?

In May Newsweek had an interesting data sheet about Israeli's nuclear capabilities.

6 World rank of Israel's nuclear arsenal by volume of bombs, according to U.S. Defense Intelligence Agency estimates.

100-250 Number of nukes in the arsenal, by the Federation of American Scientists' count

3 Number of deployments options for Israeli nuclear weapons - one by air, two by land, three by sea

2 Number of Israel's Dolphin-class, German- made nuclear submarines, which give it a second-strike capability.

Who should worry more about the other; Iran or Israel.