It's always seemed totally absurd to me how bad the razorwing is as an anti-air flyer, even though it's called a 'fighter'. In my view, this is what a Razorwing should be:
Razorwing Jetfighter
Razorwings are the Dark Eldar’s primary weapon for air superiority. In any given open-air battle, the enemy is likely to see scores of them sweeping through the skies, destroying squadron after squadron of enemy flyers with their deadly array of air-to-air weaponry.
100 points
AV 10 / 10 / 10 Flyer
Weapons: 2 Dog fighting dark lances ( 24” Str 7, AP 2, Heavy 4, skyfire only, dogfighting*)
4 dogfighting missiles ( 48” Str 8, AP 5, one shot only, lock on*, skyfire only)
Options: Nightshields 10 pts
Flickerfield 10 pts
Add a splinter rifle for 5 pts or a splinter cannon for 10 pts
Replace any dogfighting missiles with monoscythe missiles for free
Replace the dog fighting dark lances with disintegrators for free
*dogfighting – when firing at the rear armour of an enemy flyer, the weapon counts as twin-linked.
*a dogfighting missile can only be fired by “locking on”: the flyer declares it is firing the missile at a visible target in its front arc as normal (this does count as firing a weapon), however the weapon is not actually fired this turn. If the target is still in sight and range in the flyer’s next shooting phase, the weapon is fired and hits automatically, ignoring jink saves. In the turn the weapon is actually fired, it does not count as firing a weapon.