Indeed, Tides of Darkness - and specifically, Droid's model with extra turrets. Ironically, the same Orion I'm using now, with another reskin.

Although the latest stuff includes non-arbitrary damage values for all the weapons - so if you're wondering how the Shivan weapons stack up against GTVA ones, here are the numbers for some of them (a full list would be nightmarishly long):
Subach
Standard Issue Photonic Weapon
Damage: 2.45 Shld, 3.15 Hull, 1.05 Sbst
ROF: 5/sec Energy: 20 Kw
Shivan 'Pulse'
Light Repeating Plasma Projector
Damage: 1.0 Shld, 1.56 Hull, 0.94 Sbst
ROF: 10/sec Energy: 15 Kw
Kayser
Zero-Point Microburst Plasma Cannon
Damage: 9.63 Shld, 8.75 Hull, 3.06 Sbst
ROF: 4/sec Energy: 120 Kw
Shivan 'Scythe'
Zero-Point Microburst Plasma Cannon
Damage: 10.63 Shld, 8.08 Hull, 6.38 Sbst
ROF: 4.5/sec Energy: 210 Kw
Maxim
High-Velocity Kinetic Plasma Rifle
Damage: 1.5 Shld, 11.25 Hull, 7.5 Sbst
ROF: 6.66/sec Energy: 100 Kw
Shivan 'Nova'
Zero-Point Microburst Assault Cannon
Damage: 33.0 Shld, 39.0 Hull, 9.0 Sbst
ROF: 1/sec Energy: 425 Kw
I am also in the process of applying m!m's particle trail script for all ship explosions and weapon hits. With the changes I've made, the surface of a dying warship
erupts into vapor before it explodes. Below is a tech demonstration of four Kismats obliterating an Orion.

And it doesn't hurt FPS too badly.