Gnashers can make Supporting Attacks even though they have Harnessed. Their Goblin Riders cannot make Supporting Attacks.
Gnasher Dashers gain Impact Hits with the following exception instead of causing a number of hits per charging model, a charging Gnasher Dasher unit of up to 5 models causes D3 hits to a single enemy unit in base contact with the unit's Front Facing, while a unit of 6 or more Gnasher Dashers inflicts 2D3 hits instead.