Question about Guard factions

[Corsair]

I understand that Guard factions are out there to make sure that you are totally devoted to one faction, and thus are tough to build rep in, but is there a better way to get Guard rep without NPC farming? I'm trying to go guard on my LN, and even though he's been mindlessly slaughtering Hackers, Rogues, and Outcasts, LN Guard remains slightly red. I'm LN tagged and IFF'd.

And, is it worth it to enter an enemy guard system and capspam to farm Guard pilots? I did this in OpenSP, and was wondering if it was legal in-game. AND my final question: If you're not fully guard, but still trying to get Guard rep, can you enter their systems and buy their gear and ships? Like, could I get an Avenger (Theoretically) even if I'm not flashing LN Guard?

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