Crystallurgy by itself (love them shard cannons), or crystallurgy+religious (love them shard cannons that never MISS).
Throw on some Shield Deploetors to knock down the target's shields before the Shards go to work, and either they have VERY deep shields, or they take non-armor hull damage with the first salvo -- which might reduce their number of guns with which to shoot BACK, always a good thing.
...
In mods like P&N, I currently prefer Crystal+Organic (GODS ... Biocrystal armor just ABSOLUTELY ROCKS ...).
