Welcome to the forum!
If you just replaced the flat air filter, you'll see minimal gains in the upper RPMs. If you can, try looking into getting an aftermarket CAI or building your own along with a cone K&N filter. That will show better results.
Keep us updated.
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DHP V1.0, Slotted rotors, S/S Brake Lines, Custom CAI, GMPP Handling Kit, KYB's, Jimmy C DP (U-Bend delete w/ Hi-flow cat), Flowmaster Super 40's, drilled 180° T-Stat, Alt. Rewire & Alt. Voltage Booster Combo, 605's, ZZP Motor Mounts
"The only difference between me and a madman is that I am NOT mad!" - Dali