Upgrading the suspension on an Audi S4 transforms its already impressive chassis into a precision tool. An H&R Suspension Kit—whether you choose a spring/shock combo or a full coilover set—reduces body roll, sharpens turn-in, and lowers the center of gravity for a more planted feel. With parts costing around $1,200 and a weekend of careful work, you can dramatically improve handling without sacrificing daily comfort. This guide walks through the entire installation process, from preparation to final alignment, so you can enjoy a flatter cornering stance and greater confidence behind the wheel.

Why Upgrade to H&R Suspension?

H&R has been engineering suspension components for European vehicles since the 1970s. Their Audi S4 kits combine progressive-rate springs with matched dampers (or adjustable coilovers) to deliver a balanced blend of sport and street manners. Key benefits include:

  • Reduced body roll – The lower spring rates and stiffer damping keep the car flat through corners, allowing better tire contact and higher cornering speeds.
  • Improved weight transfer – A lower center of gravity reduces front-end dive under braking and rear squat during acceleration, making the car more predictable at the limit.
  • Enhanced steering response – H&R’s valving eliminates the mush often found in factory dampers, delivering immediate feedback from the steering wheel.
  • Aggressive stance – Most kits lower the S4 by 1.2 to 1.8 inches, filling the wheel well and giving the car a purposeful, race-inspired look.
  • Adjustability (coilover kits) – H&R Street Performance coilovers offer threaded spring perches and adjustable damping, letting you fine-tune ride height and stiffness for track days or daily driving.

Whether you choose a spring-and-shock kit or a coilover system, the improvement in real-world handling is immediate. Many owners report a 20–30% reduction in lap times at autocross events after swapping to H&R suspension.

Tools and Materials Needed

Before starting, gather everything you’ll need. Missing a tool mid-install can turn a day into a weekend. For this job you will require:

  • H&R suspension kit (springs + struts or coilover assembly)
  • Floor jack and four jack stands (minimum 3-ton capacity)
  • Socket set (metric: 10mm, 13mm, 16mm, 18mm, 21mm, 22mm)
  • Wrench set (combination and ratcheting)
  • Torque wrench (0–150 ft-lbs range, preferably a click type)
  • Spring compressor (manual or hydraulic; essential for safety)
  • Breaker bar (½-inch drive, 18 inches or longer)
  • Impact gun (optional but speeds up bolt removal)
  • Pry bar or large flathead screwdriver
  • Dead-blow hammer or rubber mallet
  • Anti-seize compound and thread-locker (medium strength)
  • Penetrating oil (WD-40 or equivalent)
  • Safety glasses and mechanic’s gloves
  • Torx bits (T40, T50, T55 for some Audi fasteners)
  • Magnetic retrieval tool (in case a bolt falls)
  • Floor jack pads (optional, to protect pinch welds)
  • New fasteners: upper strut mount nuts, lower shock bolts, sway bar link nuts (often recommended to replace)

If you are using a spring-and-shock kit, you will also need a vise to hold the strut assembly while compressing the spring. For coilovers, the spring perch is already adjustable, so a spring compressor may not be necessary.

Step-by-Step Installation Guide

1. Prepare the Vehicle and Work Area

Park on a level concrete surface. Engage the parking brake. Loosen the lug nuts on all four wheels by one full turn while the car is still on the ground. This prevents the wheels from spinning when you raise the suspension. Place the jack under the front or rear subframe (as appropriate for the corner you’re working on) and lift until the tire is just off the ground. Secure the vehicle with jack stands at the specified chassis lift points—never work under a car supported only by a jack.

2. Remove the Wheels

Support the lower control arm with a jack stand to keep the hub from dropping too low. Remove each wheel and set it aside. Be sure to place both front wheels away from the working area to avoid tripping. The hubs will now be accessible for suspension removal.

3. Remove the Front Suspension Assembly

The front strut on an Audi S4 (B8/B8.5 platforms) is a McPherson-type unit integrated with the steering knuckle. Follow these steps:

  • Remove the brake line bracket from the strut housing using a 10mm socket.
  • Disconnect the ABS and speed sensor wiring clips from the strut.
  • Remove the sway bar end link nut using a 16mm wrench and a hex key to hold the stud. Note the orientation of the link.
  • Remove the two bolts holding the strut to the steering knuckle. Use a Torx T50 or T55 bit depending on the model year. On some B8.5 cars, these are triple-square (M14).
  • Remove the three upper strut mount nuts from inside the engine bay. Access them by removing the cowl cover and wiper arms if needed.
  • Extract the strut assembly from the vehicle. Lower the knuckle slightly with the jack to provide clearance.

Repeat for the other front corner. Keep all hardware organized in labeled bags.

4. Disassemble the Front Strut (If Using Spring/Shock Kit)

Use a spring compressor to safely compress the original spring. Position the compressors opposite each other, tighten evenly, and avoid bending the coils. Once compressed, remove the top strut nut using a 21mm socket and an Allen key to hold the damper rod. Disassemble the old hardware: top hat, bearing plate, dust boot, bump stop. Transfer these components to the new H&R strut plus spring, ensuring the spring end coil sits in the shock’s lower spring perch groove. Reinstall the top nut to the specified torque (typically 18–22 ft-lbs). Slowly release the spring compressor. Repeat for the other strut.

Note: H&R supplies new springs that are shorter and stiffer than stock. Do not attempt to use the original springs with the new dampers—the rates are mismatched and the ride will be harsh.

5. Install the Front Suspension Assembly

Place the assembled strut into the upper mounting hole in the engine bay. Align the three studs through the chassis. Install the new upper strut nuts and torque to 18 ft-lbs (spec may vary; consult H&R instructions). Then reconnect the strut to the steering knuckle. Use new bolts if possible, and torque to 90–100 ft-lbs. Reattach the sway bar end link with the stock hardware. Torque the sway bar nut to 33 ft-lbs while holding the stud with an Allen key. Finally, clip the brake line bracket and sensor wires back into place.

6. Remove and Install the Rear Suspension

The rear suspension of the Audi S4 uses a multi-link setup. The spring and shock are separate components. First, remove the lower shock bolt (16mm). Then remove the upper shock mount nut inside the trunk (access through carpet panels). Remove the shock. Next, raise the lower control arm with a jack to relieve spring tension. Remove the spring. Compare the H&R rear spring to the original. Install the new spring—ensure the rubber isolator on the top and bottom are present. Lower the control arm. Install the new H&R rear shock by compressing it slightly. Use new upper and lower bolts. Torque the lower bolt to 60 ft-lbs and the upper mount nut to 18 ft-lbs. Repeat for the other side.

Important: The rear suspension ride height is set by the spring alone. If you desire a specific height, H&R provides a specified drop—do not attempt to adjust by adding spacers.

7. Reinstall the Wheels and Lower the Vehicle

Place each wheel back on the hub. Hand-tighten lug nuts in a star pattern. Lower the vehicle completely, then torque the lug nuts to 90 ft-lbs (or the manufacturer’s specification for your wheel type). Tighten in a star sequence. Do not fully torque while the car is in the air—the wheels must be loaded.

8. Bounce Test and Checking Clearance

With the car on the ground, press down firmly on each corner several times to settle the suspension. Drive the car forward a few feet and back to allow the bushings to find their natural position. Check wheel well clearance by turning the steering full lock both ways. Make sure no rubbing occurs with the new ride height. If you installed coilovers, adjust the damping settings to a mid-range value (e.g., 12 clicks from full stiff) before driving.

9. Final Torque Inspection

After a short test drive (less than 5 miles on quiet roads), re-torque all suspension bolts. The bushings and springs will have settled. Pay special attention to the strut-to-knuckle bolts, lower control arm ball joint nuts, and sway bar links. Any loose fastener can cause noise or failure.

Cost Breakdown and Considerations

The $1,200 figure in the title is an estimate for the H&R spring-and-shock kit. Here is a realistic breakdown:

  • H&R Street Performance coilover kit: ~$1,400–$1,600 (adjustable height and damping)
  • H&R Sport spring + Bilstein or Koni shock combo: ~$1,000–$1,200
  • Shop installation labor (if not DIY): $600–$900 (4–6 hours at $90–$150/hr)
  • Wheel alignment (post-install): $100–$150
  • Optional replacement hardware: $30–$60

If you are mechanically inclined, a weekend of DIY saves you $600–$900. Consider that an alignment is mandatory after lowering a car—the toe and camber angles will be out of spec. An Audi dealer or specialty alignment shop should be capable of adjusting the front and rear (on some models, rear camber is adjustable with eccentric bolts; on others, you may need aftermarket control arms).

Post-Installation: Alignment and Break-In

Within the first 100 miles, you will notice the suspension settling further. It is normal for the vehicle to drop an additional 1/4 to 1/2 inch after the first week. Do not perform a final alignment until after that settling period. Once the ride height stabilizes, get a four-wheel alignment. Ideal specs for a lowered S4 often include 0.5 to 1.5 degrees of negative camber front and rear, depending on your driving style. Excessive negative camber wears tires quickly; minimal toe-in at the front (0.05 degrees) keeps the car stable on the highway.

Coilover owners should re-check the damping settings after a few hundred miles. The oil in the dampers will break in, and the recommended click settings may feel softer or stiffer than initial impressions suggest.

Common Pitfalls to Avoid

  • Over-tightening spring compressors: Always compress evenly to prevent spring slippage. Never grind a compressed spring.
  • Ignoring torque specs: Under-torqued bolts can loosen; over-torqued bolts can snap. Use a torque wrench for critical fasteners.
  • Using old strut mounts: The original rubber bushings may be worn. Replace them with new H&R or OEM mounts to avoid clunks.
  • Skipping the alignment: Lowering changes the suspension geometry. Without an alignment, your tires will wear unevenly and the car may pull.
  • Not reading H&R’s specific instructions: Some kits require different spring seating methods or bump stop trimming. Follow what’s in the box.

Conclusion

Installing an H&R Suspension Kit on your Audi S4 is one of the most rewarding modifications for the money. At roughly $1,200 in parts, you gain sharper turn-in, reduced body roll, and a more aggressive stance—a combination that enhances both daily driving and weekend track use. With the right tools and a careful approach, a weekend DIYer can complete the job. For those who prefer professional help, the added labor cost is still a solid investment in handling. When done correctly, the result is an S4 that feels more connected to the road and eager to attack every corner.

For deeper technical information, consult the official H&R springs and coilovers catalog and Audizine forums for platform-specific tips. Always verify your car’s production year and suspension type before ordering. A properly installed H&R kit transforms the S4 from a comfortable gran turismo into a genuine sports sedan.