2018-2025 Audi S4

Enhance the performance and driving experience of your 2018–2025 Audi S4 with APR’s industry-leading aftermarket parts and tuning solutions. From ECU upgrades and turbo enhancements to exhaust systems and intakes, APR offers precision-engineered components designed to deliver noticeable gains in horsepower, torque, and overall responsiveness. Whether you're looking for daily drivability or track-ready power, APR's performance parts bring out the best in your B9/B9.5 S4 with proven reliability

APR Performance Packages

Shop Now
Software & Tuning

APR’s software and tuning solutions deliver refined performance engineering—precision ECU and TCU calibrations, along with inline modules, that elevate power, transmission response and driving dynamics while maintaining the integrity of your European vehicle’s factory systems.
Shop Now
Engine

APR’s Engine Hardware delivers true performance engineering—meticulously crafted intake systems, turbocharger upgrades and support components built to integrate with calibration upgrades and boost your vehicle’s breathing, response and power delivery on VW, Audi, Porsche and other European platforms.
Shop Now
Suspension and Mounts

APR’s Suspension & Mounts collection embodies European performance engineering — purpose-built coil-overs and hardware that refine ride height, minimise deflection and enhance chassis balance. Designed for precise integration, sharper control and enduring quality on VW, Audi and Porsche platforms.
Shop Now
Wheel and Accessories

APR wheels merge motorsport engineering with streetcraft — flow-formed and forged alloy constructions deliver reduced unsprung weight, optimized strength and OEM-plus fitment for Volkswagen Group performance vehicles.
Shop Now
Cosmetics and Gear

Show of your APR Pride!
Shop Now
Exhaust Systems

APR exhaust systems deliver pure European performance engineering—crafted from premium T304 stainless steel, mandrel-bent tubing and straight-through mufflers to refine note, improve flow and enhance both driver engagement and aesthetic presence on VW, Audi and Porsche vehicles.
Shop Now

APR ECU Upgrade

Delivers up to 411 HP with 551 FT-LBS (APR Plus)
Delivers up to 411-491 HP with 551-629 FT-LBS depending on octane (APR Stage 1)
Delivers up to 529-620 HP with 554-622 FT-LBS depending on octane (APR Stage 3)
Max gains of +103 AWHP and +190 AWFT-LBS (APR Plus)
Max gains of +103-171 AWHP and +190-249 AWFT-LBS depending on octane
Supports 91 AKI, 93 AKI, 100 AKI, 104 AKI, and E60-E85 fuel grades (APR Stage 1 & 3)
Max gains of +172-171 AWHP and +255-263 AWFT-LBS depending on octane (APR Stage 3)
Optional factory term limit matching limited powertrain warranty with APR Plus
Standing RPM soft limiter increased
Left-foot braking / brake boosting added
Properly rescaled performance gauges

View APR ECU Upgrade - 3.0T EA839 V6 (B9) (S4/S5/SQ5)