This is what my self imposed shieldless run wound up with as a vanguard killer:
I used two, but they're still far cheaper than anything else in this thread except Aimreh's design. None of the Vanguards have enough missile to kill them through their point defense, though you may need to pull one back to repair the nose from time to time against some of the missilier NPCs. Two of them are enough to saturate any stock NPC's point defense, which is kind of shameful really.
