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Items 1 - 16 of 16 Items
    1. 1

    Audi A4/S4/RS4 Engine ECU Upgrade

    APR's Performance Lineup for Audi A4, S4, and RS4 vehicles.

    Transform your vehicle with our Engine Control Unit (ECU) Software Upgrades. We optimize the factory engine management system to take full advantage of the engine's capabilities for large leaps in horsepower and torque, along with added features to make the driving experience more exciting.