Helfrost destructor is normally 2 damage in dispersed mode. So with the new start its damage 3. So 3D3 shots at S6, Ap-2, 3 damage is not too shabby IMO especially as you add 1 to hit and wound rolls. Makes the Stormfang very effective as a good anti-infantry with twin heavy bolters, and anti light vehicle with twin las and helfrost