The purpose of this spec is simple, peel the enemies from any distance with the reliable double ER Large Laser, finish/punish them with the AC20 when they get close. AMS provides some defense from those who intend to drive you away from your "peeling" position, and a STD engine makes sure you are not too vulnerable. It is very effective for me and still packs a good, pinpoint punch when things are in your face. It runs a bit hot when things get tough, but otherwise the 2 ER from a distance are easy to manage and very annoying for any enemy that isn't completely covered.
I like the concept, I would be tempted to turn the left arm into a shield arm, by moving that LL to the torso.
That wouldn't be a bad idea, but I noticed that no matter what, maybe because the slow torso twist, I tend to take most of the damage on the torsos, so I went for two arm-mounted lasers for additional precision and side-vertical range (with arms unlocked). Particulartly useful when and if harassed by lights.
I run a similar build. I used 2xSRM6+A in stead of the ac20, and 360xl I had collecting dust. Shoot and scoot is the name of the game.
