Cruz is the type of candidate that does well in Iowa. The Evangelicals (Huckabee and Santorum) always gets Iowa only to lose New Hampshire.
If Cruz wins Iowa (which he could given his organizational strength) the Establishment will get scared out of their minds because the choice will be Trump or Cruz!
The funniest thing will be watching the Bush supporters running towards Trump to keep out Cruz....lol
OTOH, yes, imagine the gnashing of teeth at Bush Central if the final choice is between Trump and Cruz.