The B9 A4 saloon's boot lid has a subtle factory curve, so this M4 style spoiler needs accurate positioning to sit flush along its full width. This guide covers fitting our Audi A4 B9 M4 Style Rear Spoiler, fitting the Audi A4 Saloon B9, 2016 onward (this spoiler does not fit the S4).
Tools you'll need
- Isopropyl alcohol (IPA) or a dedicated panel prep wipe
- Microfibre cloths (lint free)
- Masking tape and a tape measure
- Strong automotive adhesive such as Tiger Seal or Gorilla Glue (the supplied 3M tape is for positioning only, not a permanent fix)
- A helper to hold the spoiler steady while you check the line
Step 1: Check your fitment
Confirm you have the Saloon B9, 2016 onward, before ordering. This spoiler will not fit the S4, so double check your exact model against the listing first.
Step 2: Clean and prep the surface
Wash the boot lid thoroughly and dry it completely. Wipe the mounting area with isopropyl alcohol to remove all wax, polish and road grime, this is what the strong adhesive needs to bond properly.
Step 3: Mock the position with the supplied tape
Use the supplied 3M tape to hold the spoiler in place temporarily. This tape is only there to help you check the position, it is not designed to be the permanent fix. Measure from the same reference points on both sides so the spoiler sits perfectly central.
Step 4: Dry fit before you commit
With the spoiler mocked into position, step back and check the line along the boot lid from a few angles. This is the point to catch any alignment issues, once the strong adhesive goes on there is no repositioning.
Step 5: Bond and secure
Remove the spoiler, apply a bead of Tiger Seal, Gorilla Glue or a similar strong automotive adhesive to the mounting points, then press it back into your marked position. Apply firm, even pressure along the full width and leave it undisturbed while the adhesive cures fully, check the product's cure time before driving at speed.
Common mistakes to avoid
- Treating the supplied 3M tape as the final fix rather than a positioning aid
- Not checking fitment against the S4 by mistake, this spoiler is B9 Saloon only
- Skipping the IPA wipe down, residue is the top cause of a spoiler lifting later
- Rushing the dry fit stage and only spotting a crooked line after the adhesive is on
- Washing the car or using a jet wash within the first 24 to 48 hours while the adhesive cures
FAQs
Is the supplied tape enough to hold the spoiler permanently?
No, the 3M tape supplied is designed to help you mock the spoiler into position while fitting. For a permanent fix we recommend a strong automotive adhesive such as Tiger Seal or Gorilla Glue.
Can I drill instead of using adhesive?
Yes, drilling is an option, though most of our customers prefer strong adhesive to avoid putting holes in the boot lid.
Will this fit my Audi S4?
No, this spoiler is designed for the standard A4 Saloon B9 and will not fit the S4.
Browse the full range of car spoilers or shop Audi A4 parts to find the right fitment for your car.