The Audi RS6 4.0TT is an engineering masterpiece: a twin‑turbo V8, quattro all‑wheel drive, and a cabin that rivals luxury sedans. Yet even the factory‑equipped adaptive air suspension – refined as it is – leaves room for improvement when you want sharper turn‑in, reduced body roll, and a more connected feel. KW coilovers have become the go‑to upgrade for RS6 owners who demand both daily comfort and track‑ready handling. This guide walks you through everything you need to know – from choosing the right kit to fine‑tuning damping and maintaining your investment – so you can transform your RS6 into a truly capable performance machine.

Why Coilovers Transform the RS6 4.0TT

The RS6’s standard air suspension prioritizes ride comfort and adjustable ride height, but it introduces several compromises. Under hard cornering the air springs can allow excessive body roll, and the damping control, while sophisticated, often feels overly soft for aggressive driving. Coilovers replace the entire strut assembly with a coil spring over a damper, offering a linear spring rate and precise damping control. Key advantages include:

  • Reduced body roll: Stiffer spring rates keep the chassis flat through corners, improving tire contact and driver confidence.
  • Adjustable ride height: Lower the center of gravity for improved aerodynamics and a more aggressive stance, without sacrificing suspension travel.
  • Customizable damping: KW’s systems allow you to dial in compression and rebound independently, fine‑tuning the balance between comfort and performance.
  • Durability: Coilovers typically last longer than air springs, especially under sustained high‑performance use.

For the RS6 4.0TT, the sheer weight (over 4,800 lbs) and torque (up to 627 lb‑ft in some trims) demand a suspension that can manage rapid weight transfer. KW’s engineering targets exactly that – offering kits that maintain the car’s grand‑touring nature while unlocking its true potential.

Step 1: Understanding the KW Coilover Lineup for the RS6

KW offers three main families of coilovers for the C7/C7.5 RS6 (2013‑2018) and the C8 RS6 (2020+). Each is designed for a specific use case:

KW Variant 1 (V1)

Entry‑level, fixed‑damping coilovers with adjustable ride height. The damping is pre‑set at the factory to a sporty but compliant level. Best for daily drivers who want a lower stance and improved handling without the need for adjustments.

KW Variant 2 (V2)

Adds independent rebound damping adjustment while the compression damping remains fixed. This allows you to fine‑tune how the car recovers from bumps and corners. Ideal for enthusiasts who occasionally visit a twisty road or autocross.

KW Variant 3 (V3)

The top‑tier offering with both rebound and compression damping adjustable separately. The V3’s “Digressive” piston design provides a plush ride over small imperfections while still offering firm support under high loads. This is the choice for track days and serious performance driving.

Note: For the C8 RS6, KW also offers the KW DDC (Direct Damping Control) system, which integrates with the factory electronic damping system, allowing you to retain adaptive modes (Comfort, Auto, Dynamic) while replacing the air springs with coil springs. This is a unique solution for those who want coilover performance without losing factory convenience.

When selecting, consider your primary use. If you only drive on public roads, V2 is a sweet spot. If you regularly attend track events or want the ultimate control, invest in V3 or DDC. For more details, visit KW’s official website for fitment guides and specifications.

Step 2: Pre‑Installation Planning and Preparation

Before you touch a wrench, careful planning saves hours of frustration. Here’s what you need:

Tools and Equipment

  • Floor jack and four jack stands (or a lift)
  • Torque wrench (capable of 150 Nm / 110 lb‑ft)
  • Hex/Allen keys (usually 5mm, 6mm, and 8mm)
  • Spring compressors (if disassembling MacPherson struts – not always required on RS6 front)
  • Breaker bar and socket set (metric, 13‑21mm)
  • Wire brush and penetrating oil (to loosen rusted bolts)
  • Alignment tools or a plan to visit a shop afterwards

Workspace

A flat, level concrete floor is ideal. If working on gravel or uneven ground, ensure the vehicle is securely supported. The RS6’s weight makes safety paramount – never trust a jack alone.

Parts to Have on Hand

  • New top mounts (recommended to replace with coilovers if included; some KW kits use your factory mounts)
  • Anti‑seize compound for adjuster threads
  • Loctite (medium strength) for critical suspension fasteners
  • If your RS6 has air suspension, you may need a scan tool to deactivate the system and avoid error codes – some owners opt to code out the air suspension module. Consult forums like RS6.com for specific procedures.

Also, consider a four‑wheel alignment immediately after installation. Coilovers alter ride height and camber, which will quickly wear your tires if left unchecked.

Step 3: Installation – A Detailed Walkthrough

Installing KW coilovers on an RS6 4.0TT is a moderately difficult job, taking 6‑10 hours for a first‑timer. Professional installation costs typically range $800‑$1,200. Below is a condensed but accurate procedure. Always consult the specific KW manual for your chassis.

Front Axle

  1. Remove the wheel and support the lower control arm with a jack.
  2. Disconnect the anti‑roll bar link from the strut.
  3. Remove the three top mount nuts under the hood (accessible after removing the cowl and wiper assembly on some models).
  4. Loosen the pinch bolt that secures the strut to the steering knuckle. Penetrating oil is essential here – these bolts often seize.
  5. Remove the strut assembly by lowering the control arm enough to slide the strut out.
  6. Disassemble the factory strut (if using your top mounts) or install the KW top mounts. Follow the manufacturer’s spring compressor instructions – the spring is under tension.
  7. Assemble the KW coilover per the included guide. Typical ride height pre‑setting is 20‑30mm lower than stock. Set it to a mid‑range value for now.
  8. Install the new coilover in reverse order. Tighten the top mount nuts to manufacturer torque (usually 20‑30 Nm) and the pinch bolt to 70‑90 Nm plus 90° angle tighten.
  9. Reattach the anti‑roll bar link and torque to spec.
  10. Repeat on the other side.

Rear Axle

The rear is similar but requires accessing the top mounts inside the trunk (remove trim panels). The springs are separate from the damper on some generations – the KW kit may replace both with a combined unit. Key steps:

  1. Support the rear subframe or trailing arm.
  2. Remove the lower damper bolt and the top mount nut.
  3. Remove the spring (if separate) and install the KW spring/damper assembly.
  4. Torque all bolts with the suspension under load (car on the ground).

Important: After installation, lower the car onto its wheels before fully tightening the lower control arm bolts (the bushings must be loaded to avoid premature wear).

For a visual guide, many RS6 owners document their builds on Audizine and YouTube. Search for “C7 RS6 KW coilover install” for step‑by‑step videos.

Step 4: Setting Ride Height and Damping

Once the coilovers are installed, you must set the ride height and damping to match your preferences and driving conditions.

Ride Height Adjustment

KW coilovers use a threaded lower bracket (perch) to adjust height. Measure from the center of the wheel to the fender lip. A common street drop is 25‑35mm front, 20‑30mm rear. For track use, you may go lower, but watch for tire rub on the inner fender at full bump. Always adjust both sides equally to maintain corner balance. After setting height, bounce the car a few times to settle the suspension, then re‑torque the pinch bolts with the car on the ground.

Damping Tuning

  • KW V1: No adjustment – damping is pre‑set. If the ride is too harsh or too soft, you will need to reassess your spring rate choice.
  • KW V2: Use a small screwdriver to turn the rebound adjuster (typically 16‑20 clicks). Start at 12 clicks from full hard (recommended baseline). For a softer rebound, go softer (fewer clicks from full hard?). Actually, standard baseline is usually 12 clicks from full soft. Check the manual. Adjust one click at a time per corner and test.
  • KW V3: Separate adjusters for rebound (top) and compression (bottom, 16 clicks). Start with rebound 12 clicks from full soft, compression 10 clicks from full soft. Then fine‑tune: increase compression to reduce body roll, increase rebound to control pitch under braking.

Keep a log of your settings and how the car feels. Over several drives you’ll find your sweet spot. For a daily driver, aim for a controlled but absorbent feel – you shouldn’t lose fillings over expansion joints.

For more in‑depth tuning, KW provides recommendations on their support page.

Step 5: Long‑Term Maintenance and Care

KW coilovers are built to last, but they require periodic attention to stay in top form:

  • Visual inspection: Every 6 months or 5,000 miles, check for oil leaks (around the damper shaft), bent adjuster screws, and corrosion on the threads.
  • Clean the threads: Use a soft brush and WD‑40 to remove road grime from the height adjustment threads. Lubricate with a light oil like silicone spray to prevent seizing.
  • Check torque: After the first 1,000 miles, re‑torque all main suspension bolts (lower strut bolts, top mount nuts, anti‑roll bar links). Heat cycles can loosen fasteners.
  • Re‑adjust height: Over time, the springs may settle slightly – expect a 5‑10mm drop after the first month. Re‑measure and adjust if needed.
  • Winter care: If you drive in salt or snow, consider a protective coating or regular washing of the undercarriage to prevent corrosion on the damper bodies.
  • Rebuild service: KW dampers are serviceable. After 50,000‑60,000 miles, they may benefit from a rebuild (new seals and oil). Costs are modest compared to new coilovers.

By following these steps, you’ll keep your KW coilovers performing like new for years.

Conclusion: The Result – An RS6 That Handles Like a Dream

Upgrading to KW coilovers is one of the most rewarding modifications for an Audi RS6 4.0TT. The improvement in handling is immediate: turn‑in sharpens, the car feels planted through fast sweepers, and yet the ride remains compliant enough for daily errands. Whether you choose V2, V3, or DDC, the key is proper installation and careful tuning. The five steps outlined here – understanding the product, selecting the right kit, installing meticulously, adjusting ride height and damping, and maintaining the system – will give you a transformed driving experience. Your RS6 will not just be fast in a straight line; it will carve corners with athletic precision, matching its incredible powertrain with a chassis that inspires confidence. Enjoy the drive.