Lets look at the Raider. A very fast open topped skimmer. Moving flat out we can easily move 24" with aethersailes that increases to around 30" reliably and up to 36". Load your raider up with Torment Grenade Launchers. Any enemy unit within 6" of one or more vehicles with torment grenade launchers has their leadership suffers a -1 penalty to its leadership. Next you will want to give your raider a Shock Prow to allow it to tank shock and ram other vehicles.
This allows you to tank shock enemy units and gives them a -1 penalty to their leadership roll. A good chance to break a unit. Remember not to drive through the models carrying the melta gun if possible. The trick here is to break the enemy unit. If this happens you have a very unique Dark Eldar tactic that I am sure people will start using in the next few months.
Once you have broken an enemy unit with your tank shock they will immediately run. We all know that if you are broken and are required to make another test you automatically fail. So multiple tank shocking is possible to break a unit off the table (making them run multiple times), but this is not what I was going to get at.
Dark Eldar are very easily able to break units off the table. While this isn't your primary tactic on the field, if you set up to do this, it will happen a lot. Your opponent will cry. Nothing worse than losing a unit from mid-field that runs or drives their bikes off the table.
