The AWE Tuning Twin1 and Twin2 S4 Exhaust Systems offer outstanding performance from a true dual configuration coupled with a choice of sound volume.

Our dual tubing exhaust systems were designed in-house and feature 100% stainless steel construction with mandrel-bent dual 2.25" tubing from the downpipe outlets to the tailpipes. The Twin2 system uses two stainless steel construction mufflers to produce a deep, mellow tone, guaranteed to meet the expectations of owners looking for a civilized sound volume. For owners who want more sound from their exhaust, the Twin1 system uses just one muffler, producing a more aggressive volume. Both systems are drone free, and their tones are exquisite. The beautiful tapered tips are nicely balanced for the look of both the sedan and the shorter rear bumpered avant - and are staggered to follow the contour of the lower facia.

The 2.7 BiTurbo found in the S4 is a V6 with a turbocharger for each bank. The factory exhaust system merges the exhaust streams into a single 65mm tube after the catalytic converters.

The AWE Tuning Twin1 and Twin2 Exhaust Systems maintain individual exhaust streams, eliminating a bottleneck after the downpipes and freeing up power across the revband. As compared to stock, the diameter of the Twin1 and Twin2 tubing is a whopping 35% larger in cross sectional area. However, by not going overly large on the tubing diameter, we keep exhaust gas temps in the tubes higher, which helps keep the gas velocity up. This is in contrast to a large single tube design which can allow the gasses to cool more quickly, resulting in localized stalling along the length of the exhaust and impeded flow. Not only does the smaller 2.25" diameter tubing promote velocity through temps, but it also results in a overall ~9% increase in flow area over a single 3" system, and eliminates the turbulent section found in a typical 3" y-tube collector. Less turbulence also means better flow.

By utilizing 2 mufflers, the Twin2 is remarkably quiet, especially at cruising RPMs. Droning sounds in the cabin common with aftermarket exhaust systems is eliminated. The straight-through design of the mufflers creates a sweet melody of exhilaration when you aggressively punch the throttle. The Twin2 announces its presence subtly.

The Twin1 with its single mid mounted muffler adds aggression to the volume, with a snarl during full throttle, and spectacular burbles and pops during lift throttle. Yet during cruising rpms it also remains remarkably quiet and drone free. The Twin1 speaks with authority..

Below is a .WMV video offering both interior and exterior sound clips of the Twin1. Please note that the video has been significantly compressed for download.

Below are some videos (all the same footage) of the interior of our 2001 S4 Avant as fitted with the Twin2 Exhaust System. Please note that the video has been significantly compressed for download.

Below are 2 external videos of our 2001 S4 Avant as fitted with the Twin2 Exhaust System. Please note that the video has been significantly compressed for download.

As you can hear, the note is a complex mix of restrained aggression and refinement.

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The AWE Twin1 and Twin2 S4 Exhaust Systems are part of the complete AWE S-flo system encompassing the AWE S-flo Intake System, Downpipes, and RSK04 turbo kit.