Don't be too disappointed if things go wrong your first tourney - The Power Level system is decent if you're going for scenic, but not at all for balance. 1 PL can be anything between 15 or so and 40 points, so PL games tends to get ruled by armies that can throw a lot of upgrades on their units, as those don't usually cost PL. Example: A basic Tau Commander in a battlesuit costs the same 7 or 8 PL stock as he does with full upgrades and Big Honking Guns, so you can guess what will be placed on the table.
Farseer, potential source of Mortal Wounds. He's... kinda questionable in my eyes. Not sure what your plan for him is. He's not quick enough to keep up with your CC elements, Natural Leader provides free Guide but only if he's close... the Dark Reapers seem the obvious target to stay near, but the Exarchs rerolls 1s anyway and Maugen Ra is already providing everyone else rerolls on 1s just STANDING there. Doom is good but 24" IS a limited range, and Executioner also indicates you mean to go stomping into danger I suppose...
Maugan Ra: Can't complain about 8 improved Shuriken Cannon shots plus the reroll aura, though I'm not really sure how he'll hold up for his PL.
Dark Reapers, excellent choice. Went up in points recently, but their PL remains the same. While having the extra Exarch is nice, do consider the fact that you can only toss your psychic bullshit on ONE group though.
Dire Avengers: Solid for holding objectives.
Striking Scorpions: Yay ninjas. You lack transports so you'll need to deep strike these, and can't guarantee the charge to the relative safety of CC though. Iffy on these but potentially good.
Swooping Hawks: Should work just fine in the anti-infantry role. Which IS filled out fairly well, come to think of it.
Banshees: You need to find a transport for these. They're just too fragile to walk across the board. Effectively free advancing helps them get in cover, but they'll stil . You CAN keep them close to the Reapers as a counter-charge unit, though it seems a waste. If you do, keep them far enough that an enemy can't charge the Banshees and lock the Dark Reapers in combat still.
Overall note: You currently have 2 HQs, 2 Troops, 3 Heavy Support, 2 Elite and 1 Fast Attack. Spearhead Detachment with a CC element, then?
One problem is that your list is VERY fragile right now. As your major source of anti-vehicle and a very good source of anti-infantry, your Dark Reapers are the core of your army, and you don't have many of them (8 wounds is all that is needed to remove them as a concern).
They WILL get targeted, if the enemy knows what he's doing - usually a good assumption to make, you might even get pleasantly surprised.
You lack obvious (vehicle) targets for enemy anti-vehicle weaponry, so guess where that will be going? Vehicle/Battlesuit heavy lists will be a problem for this reason (likely mitigated if you get first turn).
Close combat lists built for deep striking might be a bother - mostly because they can likely roll up your own CC element before it gets to fight. If you meet such a list, probably better to keep your own CC in reserve where possible so you can at least get a revenge strike off when the enemy deep strike inevitably lands on your Dark Reapers.
Suggestion: Unless you have a plan for the Farseer I'm not seeing, it seems he needs to be walking with the Dire Avengers and/or Banshees, and walking out in the open with your fragile space elves seems a bad idea. I'd say trade him and a squad of Dire Avengers in for an Wave Serpent kitted out with Everything. It'll give your Banshees and Scorpions something horribly dangerous to ride in.