Blade Autostyling
Audi A4 B8 Rear Diffuser — S4 V1
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Fits the Audi A4 B8, 2008 onwards — standard rear bumper, twin exit each side. Not the A4 B9 — different bumper.
The rear valance on the Audi A4 B8 is flat, and from behind the car looks unfinished next to the rest of the range. This rear diffuser adds the cut-outs and the depth the standard bumper lacks: matte black out of the box, taped and screwed to the underside of the bumper, and nothing is cut.
About the rear diffuser
A one-piece rear diffuser in Blade Autostyling's S4 V1 design that sits in the lower centre of the rear bumper around the exhaust. It is vacuum-formed plastic, which keeps the part light and lets it flex over a knock rather than crack.
It arrives in black with the protective film still on, ready to go on the car. Once fitted the rear of the car has the depth and the shadow line it was missing.
Will it fit your Audi?
| Model | Years | Fits |
|---|---|---|
| Audi A4 B8 — standard rear bumper | 2008 onwards | Yes |
| A4 B9 | No — different moulding |
Specification
| Material | Vacuum-formed plastic |
| Finish | Gloss Black , ready to fit |
| Pieces | 1 |
| Fixing | Automotive double-sided tape and screws into the underside of the bumper |
| Fitting time | About an hour |
| In the box | One piece, protective film applied. Tape and screws are not included — use a good automotive double-sided tape such as 3M and 4mm self-tappers. |
| Part no. | CW-23 |
Fitting it
Clean the lower bumper with panel wipe. Dry fit the diffuser around the exhaust and check the cut-outs line up before the backing paper comes off. Warm both surfaces, press from the centre outwards, then add the screws into the plastic underside of the bumper. Leave it 24 hours before a jet wash.
Delivery, fitting and returns
Delivery is £20 to any UK or Ireland address, on every body kit part. Or have it fitted at Blade Performance in Portadown for an extra £20 — supplied and fitted the same day, and we warrant the fit. Check the diffuser against the car before the protective film comes off, and let us know about any transit damage within 48 hours of delivery.
What it won't do
The exhaust layout has to match — check the cut-outs against your tips before ordering.
It does not change the exhaust note or the tips; it is a styling part.
It is not injection-moulded ABS. Vacuum-formed plastic is lighter and more forgiving on impact, but it is thinner, and it is not a structural part.
Frequently asked questions
Does the Audi A4 B8 rear diffuser need painting?
No. It is supplied in matte black and goes straight on the car.
Does it need drilling?
Tape holds the alignment and screws into the plastic underside of the bumper hold it for good. Nothing goes into bodywork or paint.
Will it fit my exhaust?
Only the layout on the fitment line above. Check the cut-outs against your tips before ordering.
Can I collect it or have it fitted?
Yes. Collect from the shop in Portadown, or book it in and we fit it while you wait.
Complete the kit: pair it with a front splitter and side skirts for the full look.
See the rest of the Audi A4 B8 body kit range.
Directions
When Will i get my order
We aim to dispatch orders within 1 working day using Fastway 48-hour delivery. Once your order is on its way, you’ll receive tracking details so you can follow your delivery. Please allow extra time during weekends, bank holidays or busy periods.