You should already have voodoo going long before viper fighters show up so with some pink ship luck, the best way to fight colonial marines is to capture them all with impalers.
You mean those things that go down with one well-placed EMP grenade like with all other HWPs?
Pink Ship Luck remains LUCK for getting the craft sheduled AND having the actual item spawned among the loot.
I had 3 ships and not a single impaler so far (thus leaving me with 0 and my very first will die for research).
So I adapt to the RNG and just bio-dagger the marines to death, playing around the shield with a total NOT LUCK BASED solution.
EMP grenades are one of the newest additions and you better have even more LUCK to get good spawning maps to get your potshots down onto killer-droids or pay in bloodmoney to get the nuclear component needed to manufacture those things.
If I can't get the RNG loot or the investment doesn't look too healthy to not ruin the process entirely, I sit back and start to find 'alternatives'.
Sectopods will be rough for me rocking the grey codex but hey we got MILLIONS of ways to bombard a 2x2 target into a steaming pile of slag without risking to get cut in 2 by it's powerful laser. Also testing the more-tanks-mod to see which tank-design is the most badass and simply abuse the fuck out of it.