My Slave I will be delivered shortly so I build this list and I can not wait to try it out!
What do you think about it?
Kath Scarlet (57) Firespray-31 (38), Ion Pulse Missiles (3), “Mangler” Cannon (4), Push the Limit (3), Gunner (5), Engine Upgrade (4)
“Whisper” (42) TIE Phantom (32), Rebel Captive (3), Fire-Control System (2), Veteran Instincts (1), Advanced Cloaking Device (4)
It's somewhat the list i'm using actually, and it works very well, my last match erased a Rexler Brath/Vader list in 4 turns.
On a side note, PTL in a Firespray is not the best choice, makes it very predictable to clear stress, so i would change it for Predator or Outmaneouver, maybe even Expert Handling. You can also try Flechette Cannon with Kath, (putting a double stress can be perilous, tell Soontir or Carnor xD).
As for that Whisper is one of my variants, but i tend to use it with Recon Specialist (just in case my red dice is not inspired).
I use the bombs as blocker stops, you ionize them and let Whisper finish them while you move to engage others or the oinized ones with rear arc.
Kath Scarlet (58) Firespray-31 (38), Ion Bomb (2), “Mangler” Cannon (4), Predator (3), Gunner (5), Engine Upgrade (4), Slave I (0), Additional Munitions (2)
“Whisper” (42) TIE Phantom (32), Recon Specialist (3), Fire-Control System (2), Veteran Instincts (1), Advanced Cloaking Device (4)
My Slave I will be delivered shortly so I build this list and I can not wait to try it out!
What do you think about it?
Kath Scarlet (57) Firespray-31 (38), Ion Pulse Missiles (3), “Mangler” Cannon (4), Push the Limit (3), Gunner (5), Engine Upgrade (4)
“Whisper” (42) TIE Phantom (32), Rebel Captive (3), Fire-Control System (2), Veteran Instincts (1), Advanced Cloaking Device (4)
Its a good list!
The only problem is push the limit on Kath is not great. Predator is much better. You can even use predator to re-roll any hits on your mangler shot so that only 1 crit is dealt. This means as long as your opponent rolls 1 evade, they take a stress and you activate gunner and actually try to roll high damage 
Blade is right, make your opponent to force a stress evading at least 1 crit and reroll with Predator, i once thought in Blaster Cannon for Kath, in order to force my opponent to cancel the crits first (using the Recon Spec+ Calculation combo) but it only works at Range 1 and that's a down thumb, but could work.
And what about VI on Kath? In my experiance so far I love to use VI because it gives me tactical advantage.
I just wrote up a list last night using Kath to put the stress on before finding this thread:
Kath Scarlett
Mangler Cannon
Calculation
Mara Jade
Redline
Plasma Torpedoes
Extra Munitions
Ion Pulse Missiles
FCS
Twin Ion Engine MkII
Backstabber
I like Calculation combined with Mangler because now you're generating more crits, which causes Kath's ability to trigger more often. I plan to just joust Kath directly into the heart of the enemy squadron, firing away and then triggering Mara Jade, stressing and hopefully double stressing multiple ships, allowing Redline and Backstabber to get into position to deal some serious damage. I suppose anyone not stressed can get Ion from Redline to maintain control. Although, I haven't thought of giving Kath a title and Ion Bombs, which sounds cool too!
Edited by ZogwortI just wrote up a list last night using Kath to put the stress on before finding this thread:
Kath Scarlett
Mangler Cannon
Calculation
Mara Jade
Redline
Plasma Torpedoes
Extra Munitions
Ion Pulse Missiles
FCS
Twin Ion Engine MkII
Backstabber
I like Calculation combined with Mangler because now you're generating more crits, which causes Kath's ability to trigger more often. I plan to just joust Kath directly into the heart of the enemy squadron, firing away and then triggering Mara Jade, stressing and hopefully double stressing multiple ships, allowing Redline and Backstabber to get into position to deal some serious damage. I suppose anyone not stressed can get Ion from Redline to maintain control. Although, I haven't thought of giving Kath a title and Ion Bombs, which sounds cool too!
I do not know, but I would never fly Kath directly in to the enemy...she will be vaporized very quickly and than the Redline...please try this list out and let us know how was it.
I find kath with calculation does just fine, even better if you can squeeze a recon specialist onto her. Or if you really want to try for gunner double stress use marksmanship. The way I fly her I tend to shoot primarily out of the rear arc so mangler doesn't do much good for her.