So i've decided on my list which is:

Krassis + HLC

Bounty Hunter + Gunner

The question is, the remaining points i'm between Backstabber with stealth device or howlrunner. What do you reckon?

I'm guessing backstabber would simply last longer due to the stealth device so was leaning more towards that.

Of the two, in this list, I'd go with the 19 point Backstabber + Stealth.

Heck, I'd consider going with Dark Curse + Stealth, as you've got plenty of damage in your Firesprays.

Hmm, that would be an interesting choice. I may well do that.

Thanks for the input.

you could upgrade ur BH to Kath Scarlet with Expert Handling, this leaves u 12pts for an Academy Pilot.

Kath Scarlet + Expert Handling + Gunner (45)

Krassis Trelix + HLC (43)

Academy Pilot (12)

Now i know what ur thinking... Academy Pilot isnt as good as backstabber or dark curse but that is exactly why it is good because ur opponent will not view it as a threat and likely ignore it (especially if it stays at long range and uses evade or focus for defending itself). In my experience a lowly Academy Pilot will chip away and get in more damage that it should and at PS1 it can become a timely blocker if it needs to.

Having the ability to barrel roll on a firespray is REALLY good. its large base means you can really move a large distance when u roll putting Kath in positions ur opponent will not expect her to be in opening up opportunities for u to get in free shots and/or totally move out of enemy firing arcs

You have two massive threats and a non-threat that will be ignored. Krassis will likely be their primary target. None likes getting pounded by 4 attack dice every turn - keep Krassis out of the up close combat and use hit and run tactics - dont hesitate to zoom away from danger and use ur rear firing arc on the way! reposition for the HLC assault every few turns if they rush at you and flank with Kath and Academy Pilot.