Does He /She shoots four or three times from the rear arc , i don't get it .

And in which phase does the ability triggers?

If i play Marksmanship , Baffle , Experimental Interface,Special Ops Training ,i could trigger the ability in the activation phase and shoot twice on a target facing my rear-arc , right or wrong?

After that, i have my regular attack left , which could be also performed twice shooting form rear-arc, right or wrong ?

Combined with Youngster + Expose , Backdraft and or some other Crack TIE's there is an evil alpha strike potential, right or wrong?

Wrong.

Your options with a /sf with the title, whenever you shoot (including QD's special shot from losing a shield):

Missile out of front arc. Nothing out of rear arc (NB, this isn't an option you can use for QD's extra attack from losing a shield, that's primary only)

2 die primary out of front arc (not using title at all, rare that you'd want to do this, but ou might for some reason)

3 die primary out of front arc (using title to add a die only).

2 die primary out of rear arc only. No extra dice, no extra attack.

2 die primary out of front arc then 2 die primary out of rear arc.

You cannot use the title to shoot twice from the rear arc.

QD is great, by the by. Getting two opportunities to shoot in a round with basically maximum mods is really strong. But it comes at a VERY high cost.

This Ship gives me Brainknots , i dont know why

So you say:

Trigger ability ,shooting with two die from the front ,not adding the die and "trigger"the title ,shooting with two from the rear .

And i could do that with my regular attack again this round ,so i could have all together, 2 attacks to the front and 2 to the back , both with two die if i am not in range 1.

Correct ?

Yes now you have it, just make sure that if you are wanting to use the title and fire from both front and rear you fire front first. And don't feel bad it has given lots of people brainknots.