FREE SHIPPING on all MSS Adjustable Lowering Springs!

APR 4.2L FSI V8 ECU Stage 1 Upgrade




APR's ECU upgrade is available in octane-specific variations and is conveniently flashed to the vehicle's factory ECU through the OBD-II port without any physical modification to the factory ECU.

The ECU's MED 9 engine management system is responsible for proper operation of the engine during constantly changing environmental and load conditions. With built in compensational data for environmental variables and varying load conditions, the factory ECU is far more complex and intelligent than units found in other makes and marques. 

Not only does APR's Stage 1 ECU Upgrade give you higher peak numbers of 444 HP and 372 FT-LBS of torque, but also gains of up to 24 HP are available at higher RPM's!

All APR Software upgrades are only available at our Joplin, Missouri retail location. In order to receive an APR software upgrade, please click here to schedule an appointment. You may either add this item to your cart and purchase online, or may also pay in store. 


 Vehicle Engine Transmission
Audi RS4 B7 4.2L FSI V8 All