The B9 introduced the second generation of the Audi A5 and marked a much larger change than the facelift that separated the earlier B8 and B8.5 models. Its sharper body lines, more technical front-end design and redesigned exterior created a strong base for carbon fiber upgrades, particularly around the lower front bumper, side profile and rear of the car.
This collection includes selected 2017–2019 Audi A5 / S5 B9 carbon fiber parts for different exterior configurations. Current options include front lips and splitters, rear diffusers, side skirts, headlight accents and rear spoilers for selected A5 S line and S5 Coupe or Sportback models. Because these parts follow the shape of the original bodywork, correct bumper and body-style identification is important before ordering.
B9 vs B9.5: Check the Front and Rear Bumper
The original B9 and the later B9.5 facelift belong to the same second-generation A5 family, but they should not automatically be treated as the same exterior application. The later facelift introduced substantial changes to the Singleframe grille, front air intakes, lower bumper treatment, side-sill design and rear diffuser area.
This distinction matters most for bumper-mounted carbon fiber parts. A front lip or rear diffuser designed around the original B9 bumper should not automatically be assumed to fit a later B9.5 vehicle simply because the basic A5 or S5 body shape remains similar. If your vehicle is close to the facelift transition, compare the bumper openings, lower edges and diffuser shape with the product photos before ordering.
A5 S line and S5 Use Different Exterior Details
Not every B9 A5 uses the same exterior. Audi equipped the A5 S line with dedicated S line front and rear bumpers, side skirts, honeycomb-style air inlet grilles and a specific rear diffuser. The S5 goes further with its own S-specific front and rear bumpers, air inlets and rear diffuser treatment.
For this reason, a carbon fiber part listed for an A5 S line or S5 should not automatically be considered compatible with every A5 B9. Front lips, splitters and rear diffusers should be selected according to the original bumper configuration rather than model year alone.
Choosing a B9 Front Lip or Splitter
Front lips and splitters are among the strongest upgrade categories for the B9 because the lower bumper already has a wide, angular shape. A well-matched carbon fiber lip can extend this factory line and give the front end a lower, more defined appearance without changing the complete bumper.
Fitment depends on the lower bumper profile, air-intake shape and mounting edge. Check whether the product is listed for A5 S line, S5 or both, and compare the installation area carefully. Different front lip designs may fit the same general vehicle range while creating very different levels of visual aggression.
Choosing a Rear Diffuser for the B9 S Line or S5
The rear of the B9 is another area where trim level matters. Audi used different rear diffuser treatments across the A5 range, while the S5 received an S-specific diffuser together with its characteristic quad oval exhaust outlets.
Before choosing a rear diffuser, confirm the rear bumper style and exhaust opening arrangement. Matching the model year alone is not enough if the diffuser profile or exhaust cut-outs are different. This is particularly important for larger full-width diffusers and designs that incorporate additional features such as a centre brake light.
Coupe vs Sportback Spoiler Fitment
The B9 A5 was offered in both Coupe and Sportback forms, and the two body styles use different rear surfaces. The Coupe uses a conventional trunk lid, while the Sportback combines the coupe-like roofline with a large rear hatch. This directly affects spoiler shape and mounting geometry.
Choose a rear spoiler according to body style first. A Coupe spoiler should not be assumed to fit a Sportback, and vice versa, even when both vehicles share the same B9 generation and model year. This collection includes separate spoiler options for selected Coupe and Sportback applications.
Side Skirts and the B9 Lower Body Line
The second-generation A5 has a pronounced shoulder line and a relatively clean lower body profile. Carbon fiber side skirts can visually connect a front lip with the rear of the car and create a more consistent lower line along the vehicle.
Side-skirt fitment should still follow the exact product application, particularly where S line exterior trim is involved. Check body style, sill profile and mounting points before installation rather than assuming that every A5 B9 side skirt uses the same geometry.
Parts That May Span B9 and B9.5
Some rear spoilers in this collection are specifically listed across both B9 and B9.5 model years. This can be valid where the relevant trunk or hatch mounting surface remained compatible even though the front and rear bumper styling changed.
Cross-generation compatibility on one part does not mean that every exterior component is interchangeable. A spoiler may correctly fit both B9 and B9.5 while a front lip or rear diffuser does not. Always follow the fitment range of the individual product instead of applying one compatibility rule to the entire vehicle.
Building a Cohesive B9 Exterior
The B9 already has a sharper and more technical appearance than the previous A5 generation, so exterior upgrades generally work best when they extend the original design language. A front lip or splitter can strengthen the lower front edge, side skirts can continue the visual line along the rocker panels, and a rear diffuser or spoiler can add definition to the rear.
Rather than selecting parts only by how aggressive they look, consider bumper compatibility, body style, ground clearance and carbon finish together. Using components with a similar visual weight across the front, side and rear usually produces a more cohesive result.
Confirm Your Audi A5 / S5 B9 Before Ordering
This collection is intended for selected 2017–2019 Audi A5 / S5 B9 exterior upgrades, but individual products do not necessarily fit every vehicle within that period. Confirm the vehicle year, A5 S line or S5 specification, Coupe or Sportback body style, and the original front or rear bumper where relevant.
For the earlier generation, browse our 2012–2016 Audi A5 / S5 B8.5 collection. For other A5 and S5 generations, visit the full Audi A5 / S5 collection. If you are unsure about fitment, send your vehicle year, model and clear photos of the installation area through our Fitment Support before ordering.
