Missile silos don't have strategic value, especially not when you have 2, 3 or 4 of them.
Look this up:
RT-23 Molodets - Wikipedia, the free encyclopedia This was a program by Soviets to make it more difficult for the U.S. to eliminate their retaliatory capability.
To be honest, Saudis don't even need a missile program, their air force (with proper training) could be enough to counter any regional threats. These inaccurate missiles could only be a viable option if Saudi could get its hand on a Pakistani nuclear warhead, and with lack of clarity in Pakistan military they might as well get them.
This just shows that Iran has already taken the wrong side as China and Russia at the moment did nothing but weakening Iran's position and selling weapons to its rivals. Iran must maintain relation with all countries but the balance must leans towards the West, its not about likes or wants, its about facing the reality and waking the **** up!