1.Put the car on flat ground, in park, or first gear with the ebrake engaged. Jack up the rear of the car with a floor jack or bottle jack using the rear jack points. Place jack stands or cribbing under the control arm. Remove the rear tires. It is good practice to place the tires under the pinch seam of the car as a safety measure if a jack stand moves or fails. 

2. Remove the three T25 torx screws that hold the back of the wheel liners to the bumper. Repeat on the other side. 

3. Pull the liner forward so you can see the two T25 screws that hold the plastic bracket to the edges of the valence. Remove both on each side. (mk7 clip shown, mk6 will be a different shape).  

4. Take note of how the bumper lip and valence lip are sandwiched inside this clip for reference when reinstalling it. Pull the outer edge of the clip towards the center of the car. Once the outer edge releases, slide the second half of the clip forward. 

5. Open the diffuser box. Remove the packaging. With the machined pockets of the baseplate facing up, slide the fins onto the baseplate until they lock into place. The fin hole should be on the top.  

6. If you are having a hard time getting the fins to click in, hold the baseplate against your chest, then grip the fin with your hands and pull it towards you to press it into place. The brass threads on the baseplate should line up with the hole in the fin. The fins have some adjustability forward and back to line them up with the retaining screw. 

7. Install the black M4 bolts using a Phillips head screwdriver. You can use thread-locker on these screws, however it is not necessary. They just need to be snug, do not over tighten. Fasteners this small can be easily stripped. 

8. Locate the M6 bolts, and nylock nuts in the hardware bag. Grab your clamps, a 4mm Allen key, 10mm wrench and a drill with the 6mm or ¼” drill bit. 

9. Hold the baseplate and fin assembly tight to the valence with the countersunk holes facing down. Place a clamp on each edge to keep it in place. Now adjust it left or right to center it. Check the outside edges, and notch in the center to make sure that your gaps are consistent all the way around. 

10. Wear safety glasses and drill the two center holes with a 6mm or ¼” bit using the baseplate as a guide. Install two bolts, and nylock nuts. Hold a wrench on top, and turn the bolt with the allen key. 

11. Now drill the remaining holes in the baseplate, and install the hardware. The baseplate has two 4mm or 5/32” holes on the sides that should be drilled last (shown above). Then install the M4 silver hardware in this hole. 

12. The spats are left / right side specific. The countersunk holes will be on the bottom. The narrow end of the spat should be closest to the wheel well. 

13. Have a clamp ready, or second set of hands to help hold it in place. 

Hold the spat up to the edge of the valence/bumper. The rear edge of the spat should line up with the valence, and the flat edge should line up with the wheel arch. 

Mark and drill the hole closest to the valence. 

Install the smaller bolt (M5), and nut. Install it snug, but with enough room to rotate the spat if needed. 

Then drill the hole closer to the wheel arch and isntall the bolt. 

14. Reinstall the valence clips onto each side. Reinstall the clip screws. Line up the fender liners, and reinstall the three screws on each side. Reinstall the rear tires. Once the car is back on the ground, torque the lug nuts.