This is an example of “the enemy of my enemy” scenario.
There is a real arms race taking place across the greater ME, and Saudi Arabia has been vocal in the past year about not being caught defenseless against Iran’s nuclear capability!
While unlikely to easily happen, it has been widely known and even publicized, Iran wants control of Saudi Arabia.
I believe these two would have a large war in the near future without any other external influence.
Yes, what we are seeing is a great rift within Islam. On one side the Sunni and on the other the Shiite. This conflict is currently the main reason there is a very hot Civil War in Syria that is bringing in the world’s great powers. Many rumors have floated for years that the Saudis already have nuclear weapons - purchased from Sunni majority Pakistan. The external meddling will ensure the war will expand perhaps beyond the Islamic world.