Knowledge is Power - At 1st level, you gain a +2 bonus to Bluff, Knowledge, Perception, Sense Motive, and Survival checks with dealing with arcane casters.
Pierce Concentration - At 4th level, when you hit an arcane spellcaster or a creature that uses spell-like abilities with a ranged attack, that creature must succeed at a Fortitude saving throw (DC 10 + Wis mod + 1/2 Inquisitor level). If the spellcaster fails, he takes a –4 penalty on concentration checks for 1 round.
Suppression - At 8th level, you add Dispel Magic to your list of spells known and gain a +2 bonus to the dispel check when used to counterspell. Once per day, you can counterspell as an immediate action.