The debate between arrow vs shahab, sejil ect is a lenghthy one, but i think what would give us a good idea of who has more advantage in the missile department would be if we know how many arrow missiles israel have. We dont know exaclty how many missiles Iran has but we can estimate with all the missiles that have 1000km+ range, iran has a lower end of approx 400 (reports say that iran has capacity of building 75 missiles w/2000km range a year [http://www.ynetnews.com/articles/0,7340,L-3636744,00.html
], shahab was introduced 2003, the rest was estm maths).
1)So if iran was to launch 150 in a full scale war, would israel have enough no. of arrows to stop the majority of these missiles (assuming it has v.high hit ratio), also we know arrow systems have six launchers?
2) and how many missiles need to hit israel for it to stop US and Israel to stop war and retreat? i.e. how many sites does iran need to hit for Israels economy to diminish to a point where continuing war would be impossibl?