Stormtrooper721, I have no idea how competitive it would be, but I think the 2 Firespray-31 ship build sounds like a ton of fun. I bet you could tweak the build a bit to respond to R5Don4 Star II's worry about how long you would be able to keep those two ships alive. First, I think you could drop both Gunners. It stikes me that the main advantage of the Firesprays with Heavy Laser Cannons is that they aren't going to miss a lot (since they roll 4 attack dice at range 3 and the opponent doesn't get an extra defense die because it is a secondary weapon). And if that's the case, then the 10 points for Gunners could be better used in other places.
As a quick digression, with a target lock the Firespray w/Heavy Laser Cannon will average 3 hits. A TIE fighter with a Stealth Device and either a focus or evade token will only average 2.5 evades. Also, remember that your second Firespray should be targeting the same ship, which should no longer have either a focus or evade token (and thus is even less likely to need the effect of the Gunner). So, let's scrap the Gunners.
The next thing I'd think about changing would be the Stealth Devices. They only impact the game until the ships take their first hit. You only have two ships for the opponent to target and the Steath Device only makes each ship as hard to hit as a regular TIE. My guess is that these would not last long. By dropping them you have an extra 6 points to play with. You're now up to 16 points to shift around.
What about upgrading the unnamed Firespray-31 to Fett and giving him a Shield Upgrade and Draw Their Fire. This build still has 6 free points to play with. The idea is that by giving Fett the Shield upgrade you make Trelix the more attractive target for your opponnet (since your opponent realizes that ship has one less hit point than Fett and should die more quickly). But then you aim to use Draw Their Fire to have Fett uses his sheild to take critical hits (and especially direct hits) that were meant for Trelix. If you find that your opponents are too clever for this tactic, you could spend 3 of your remaining 6 points to upgrade Trelix to Kath equip Kath with a second Draw Their Fire. Now whoever your opponent goes for first (and I'm assuming that your opponent will concentrate his/her fire on one ship until that ship has been destroyed) the other ship can use Draw Their Fire to protect against critical hits. The only downside to this Draw Their Fire strategy is that both Firesprays must stay within range 1 of each other to use this effect.