Improved Targeting which ignores & destroys blocking terrain (such as Iron Man from IIM). Structural Integrity Field (SIF) is in play.

I'd say that Iron Man or Cyclops with Improved Targeting could still make the attack against a character behind a wall or square of blocking terrain, but wouldn't destroy the blocking terrain, because SIF would prevent the destruction of the terrain.

Is this correct? From the wording of all said game elements, sounds right, but wanted a second opinion.

That is correct.