Upgrading your Audi A4 S‑line to the 340‑horsepower mark is a rewarding project that blends daily drivability with serious performance. The combination of a Revo Stage 2 tune and H&R suspension transforms the B8/B8.5 chassis into a responsive, confidence‑inspiring machine. Before you open your wallet, it helps to understand exactly where your money goes and what you can expect in return. This article breaks down every significant cost — from springs and shocks to software and supporting hardware — so you can budget accurately and avoid surprises.

Understanding the Core Components

The 340‑hp upgrade hinges on three pillars: a high‑flow exhaust and intake (often required for Stage 2), the engine calibration itself, and suspension that can harness the extra power. The stock Audi A4 S‑line already comes with firmer springs and sportier dampers, but the H&R kit takes things to another level. The Revo Stage 2 tune unlocks the engine’s true potential by adjusting boost pressure, ignition timing, and fuel mapping to work with a less restrictive exhaust system. Together, these components work synergistically — neither is truly effective without the other if you want a balanced, reliable setup.

The Role of the H&R Suspension Kit

H&R offers both spring‑only and coilover kits for the A4 S‑line. For most enthusiasts targeting 340 hp, the H&R Sport Springs combined with matched dampers provide an excellent cost‑to‑performance ratio. The kit lowers the car by roughly 1.3–1.5 inches at the front and 1.0–1.3 inches at the rear, reducing body roll and improving turn‑in response. If you prefer adjustability, H&R’s Street Performance coilovers add damping control, but they come at a higher price point. Regardless of the variant, the suspension upgrade is critical for putting the added 60–80 horsepower to the pavement without compromising safety or comfort.

H&R Suspension Kit Cost Breakdown

Prices vary depending on whether you choose a spring‑and‑shock combo or a full coilover set. Here’s a realistic range based on current market data:

  • H&R Sport Springs (set of four): $280 – $450
  • H&R Street Performance Coilovers (full set): $950 – $1,300
  • Shocks/Struts (if using separate springs): $550 – $850 for a matched set (e.g., Bilstein B8 or Koni Sport)
  • Installation labor: $350 – $600 (depending on shop hourly rate and whether alignment is included)

Total cost for the H&R suspension upgrade (including alignment) typically lands between $1,200 and $2,200. Going with coilovers adds adjustability but pushes the budget to the upper end. Keep in mind that many shops charge extra for cutting and welding if you opt for a custom setup; plug‑and‑play H&R parts avoid that complication.

Revo Stage 2 Tune: Software and Hardware

The Revo Stage 2 tune is the heart of your power increase. Unlike Stage 1, Stage 2 requires an upgraded downpipe (and often a full exhaust) to reduce exhaust backpressure. Revo’s calibration adjusts boost targets, fuel injection timing, and cam adaptation to safely run higher boost levels without triggering knock detection.

  • Revo Stage 2 software license: $599 – $799 (often includes a free SPS switch for on‑the‑fly map changes)
  • Downpipe (high‑flow 200‑cell or catless): $400 – $900 (brands like APR, Revo, HJS, or custom)
  • Optional intercooler upgrade: $400 – $800 (strongly recommended for sustained performance)
  • Performance intake (e.g., REVO Carbon or Eventuri): $250 – $500
  • Tuning session or flash tool (if not using a local dealer): $100 – $200

The total for the Revo Stage 2 portion, including the required downpipe, ranges from $1,050 to $2,000. If you already have a downpipe from a previous upgrade, you can subtract that cost. Many owners also choose a DSG tune (add ~$500–$700) for automatic transmissions to handle the extra torque and sharpen shift times — that cost is separate from the engine tune budget.

Why an Upgraded Intercooler Matters

At 340 hp, the factory intercooler can heat soak during repeated pulls or in warm climates. An aftermarket unit (e.g., Wagner Tuning or APR) lowers charge air temperatures by 20–30°F, allowing the Revo tune to maintain consistent timing without pulling boost. If you plan to track the car or live in a hot region, do not skip this investment. The cost of a quality intercooler is roughly $400–$750, plus installation labor.

Supporting Modifications: The Complete List

Beyond the core suspension and tune, a few supporting mods make the upgrade reliable and enjoyable. Here is what most 340‑hp builders include:

  • High‑flow intake system: $200 – $400 (improves throttle response and turbo noise)
  • Cat‑back exhaust (optional, but improves sound and flow): $500 – $1,200
  • Clutch upgrade (manual transmission): $800 – $1,500 (the stock clutch may slip with Stage 2 torque)
  • Brake pads/rotors upgrade: $300 – $700 (stoppers need to match the extra pace)

Budgeting an additional $1,200 to $2,500 for these supporting mods is realistic. If you are on a strict budget, prioritize the downpipe and clutch (if manual). The intake and cat‑back can wait, though they do enhance the experience.

Total Cost Estimate

When you add up all the categories, the total investment to upgrade your Audi A4 S‑line to 340 hp with H&R suspension and Revo Stage 2 tune falls in this range:

  • H&R suspension (including installation): $1,200 – $2,200
  • Revo Stage 2 tune with required downpipe: $1,050 – $2,000
  • Supporting mods (intercooler, intake, clutch, brakes): $1,200 – $2,500

Grand total: $3,450 – $6,700. The wide range reflects choices between basic spring kits and coilovers, whether you need a clutch, and if you do the labor yourself. DIY installation on the suspension and intake can save $500–$800, but professional tuning and downpipe work are best left to experts.

Additional Considerations for a Successful Build

Upgrading a modern Audi involves more than just buying parts. The B8/B8.5 platform has known weak points that you should address while the car is apart.

Cooling System and Oil Health

With increased boost comes higher heat. Consider upgrading the radiator or adding an auxiliary oil cooler if you drive aggressively. Revo’s Stage 2 tune runs safely within factory cooling limits for daily use, but prolonged track sessions may push temps beyond optimal. A low‑cost oil cooler kit (around $200–$400) provides peace of mind.

PCV and Valve Cleaning

The EA888 Gen2 and Gen3 engines are direct injection, so carbon buildup on intake valves is a known issue. If your A4 has more than 60,000 miles, consider a walnut blasting service (around $400–$600) before installing the tune. Clean valves ensure the Revo tune adds power consistently without misfiring.

Transmission Tuning

For DSG equipped cars, a Revo or TVS Engineering DSG tune is strongly recommended. The factory shift logic may not hold gears properly with the extra torque, leading to slipping or harsh engagement. A DSG tune adds roughly $500–$700 to your budget but dramatically improves drivability.

Performance Gains and Real‑World Expectations

After the full build, your Audi A4 S‑line will produce approximately 340 hp at the crank (around 290–310 whp depending on the dyno and drivetrain loss). Expect 0–60 mph times in the 4.5–4.8 second range — a full second quicker than stock. The H&R suspension eliminates the floaty feel, and the car corners flatter with improved steering feedback. On the highway, passing power becomes effortless, and the exhaust note (with the downpipe) gains a purposeful growl without being obnoxious.

Fuel economy will drop about 2–3 mpg under normal driving, but that is a small price for the significant performance uplift. Daily driveability remains high; the Revo tune does not make the car jerky or hard to live with, provided you use the correct octane fuel (premium 93 or 98 RON).

Where to Buy Parts and Find Expertise

Reliable sourcing matters. For H&R products, the official H&R website lists authorized dealers. Revo’s software is available through their global dealer locator. For a community perspective, the Audizine forums have dozens of build threads that can confirm parts compatibility and expected results. For high‑flow downpipes and intercoolers, brands like Wagner Tuning and 034Motorsport are well‑regarded; check their official sites or catalog retailers like ECS Tuning.

Conclusion

Upgrading your Audi A4 S‑line to 340 hp with H&R suspension and Revo Stage 2 tune is a substantial investment, typically falling between $3,500 and $6,700. The payoff is a car that handles like a true sport sedan, pulls hard from any speed, and retains daily comfort. By planning for the required downpipe, intercooler, and clutch (if manual), you avoid the trap of a partial build that leaves power on the table. Work with a reputable installer and ensure all supporting mods are done correctly — your A4 will reward you with years of thrilling driving.