Audi B6/B7 S4 and B8 S5 4.2L V8s are factory-equipped with two auxiliary radiators. -one on the left side and another mounted on right. This factory system is effective for sustained high-speed Autobahn use. However, it is proven inadequate when pushing a car hard on road courses and twisty country back roads.

USRT deletes the right side oil/water exchanger and replaces it with a more efficient 16-row air-cooled unit positioned in front of the radiator. Oil temperature management is much improved.
This configuration will also allow cooler air into the engine's intake that typically passes through that aux radiator and is subsequently heated.
This is how stress is relieved from cars run continuously under heavy load.
Place your heat exchanger where it gets air flow, is fully serviceable, and without any double stacking. That's really all there is to it. Mounting orientation is up to you (but fittings up is typically cleanest to work with). See our Oil Cooler + Electric Fan Mounting Kit for a simple yet rugged mounting solution.

Note: Kits are SOLD OUT. New availability information will be posted soon.