If you intend to use your army in a tournament, you need to understand that you are going to face some tough enemy units. Furthermore, other than Tyranids and possibly Orcs, most armies make significant use of vehicles, because of the flexibility they provide with their mobility, as well as their ability to protect infantry with their armored hulls. As listed, your army doesn't seem well prepared to deal with these types of threats. One set of Twin Linked Bright Lances and one EML on a fast shooting Dark Reaper exarch just aren't going to cut it. You also need to bear in mind that the Night Spinner is not in the Eldar Codex. Therefore, although you can use it in Apocalypse, you cannot use it in a standard 40K tournament.
Here's my recommendation:
Farseer: Give him Fortune instead of Guide, the DA (and the Farseer himself) will live longer.
Dire Avengers: Modify the Exarch; give him the Power Weapon, Shimmershield, and Defend. Keep the Farseer with them, and you'll have a pretty durable scoring unit. Add Yriel and they become a legitimate threat in close combat.
Swap the Night Spinner for the Fire Prism: Makes the list legal and gives you more firepower too.
Wraithlord: Upgrade to EML and Bright Lance; more anti-vehicle firepower. The Fire Prism can thin out troops if necessary.
Dark Reapers: I'm not a fan, I think you have better options in the other models available to you.
Try a list like this:
(155) Yriel
(130) Farseer w/ Doom, Fortune & Runes of Warding
(162) Dire Avengers x10; Exarch w/ Power Weapon, Shimmershield, Defend
(145) Wave Serpent w/ Twin-Linked Bright Lances, Spirit Stones
(192) Pathfinders x8
(136) Guardian Defenders x10 w/EML, Warlock w/Embolden & Spiritseer
(170) Fire Prism w/ Shuriken Cannon, Holo-Fields, Spirit Stones
(155) Wraithlord w/ Bright Lance & EML
Total:
1245 Points
3 Scoring Units, 8 Kill Points
31 Infantry, 2 Vehicles, 1 Monstrous Creature
Its not perfect, but the only new model you would need to purchase is a single Warlock. It provides a significant improvement in your Anti-tank and close combat capabilities, and although you pay a price in anti-horde shooting, I think your list will be more successful overall. Good Luck!
C.S.