One common complaint that I have heard regarding Dark Eldar is their susceptibility to template weapons. Dark Eldar's primary Troop is the Warrior - mounted in a Venom or Raider (when was the last time you saw a foot mounted Warrior Squad?). By flaming an open topped vehicle and hitting the occupants, our opponents are getting a chance to both glance our flimsy vehicles and fry the guys inside.
The best solution that I have found in the Codex is the bubblewrapping with the Beastpack. A squad of 10 Khymera and 2 Beastmasters has a very large footprint and can easily block a Drop Pod or Dreadknight from coming in too close. For 120 points this unit is a great buy, and can actually help with punching rear armor 10 against armies that carry it.
The biggest downside is that it competes with other Fast Attack choices, making them a tough sell. However, if you can sacrifice the firepower of Scourges or Razorwing Fighters, the Beastpack might be a great buy to help preserve your vehicles.