In all honesty, 13 points maybe. A rear arc is nice but for basic academy ties I wouldn't want to spend more that a point, mayyybe 2 on upgrading them.
One of the design thoughts I've had is that there are certain upgrades so useful that they simply can't ever be cost effective. Like: imagine a Tie Fighter only mod that gave you 50 red dice. Try pricing it in such a way that it would be worth putting on a low-durability platform with _every gun on the opponent's side aimed at said platform_. Sure, you could 1-shot a Falcon (I mean, presumably. Your dice would have to be very, _very_ cold not to!), but I'd guess you wouldn't survive the first round of firing. And- given that Han Shoots First- maybe your Tie wouldn't even last long enough to use its super gun.
So how do you price that fairly? I honestly don't think you can.
A rear arc on a standard Tie would be easier to price, but I do think starts to run into the issue where "fair" is either so low that it's an autoinclude, or so high that it never gets used.
