I don't doubt the claims that a rocket can take out Israeli/American tanks. I don't know how well the Israeli Trophy system works to protect those tanks either. However, when it comes to sinking an American capital ship...If Iran sinks one or cuts off oil in the Gulf, Iran has sealed its fate.
Army: Blast in Korean DMZ wounds two South Korean soldiers (Reuters)
from the article: Revolutionary Guards: Iran can penetrate Israel's Merkava tanks