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Introduction: Unlocking Your Infiniti Q60’s Potential
The Infiniti Q60 stands as a premium grand tourer, blending striking design with a refined, turbocharged powertrain. While the 3.0-liter twin-turbo V6 delivers respectable output from the factory, enthusiasts know that the real performance lies dormant, waiting for the right upgrades. Among the most impactful and accessible modifications is a high-quality cat-back exhaust system. The HKS Legamax exhaust, specifically engineered for the Q60, offers a compelling mix of power gains, weight reduction, and an evolved exhaust note. This comprehensive guide provides a detailed cost breakdown for installing an HKS Legamax system on your Infiniti Q60, targeting a verified 20 horsepower increase. We will cover every expense, from the unit price and labor to ancillary parts, so you can budget accurately and make an informed decision for your build.
Understanding the HKS Legamax Exhaust System
Before diving into costs, it is critical to understand what the HKS Legamax system brings to the table. HKS is a premier Japanese tuning house with decades of experience in forced induction applications. The Legamax series is designed for street-driven sports cars that demand a balance of performance, sound refinement, and OE-like fitment. For the Q60 VR30DDTT engine, the system replaces the restrictive factory exhaust from the catalytic converters back. Constructed from high-quality T304 stainless steel, it features smooth mandrel bends to minimize backpressure and improve exhaust gas velocity. The system often incorporates a larger diameter piping and a straight-through perforated core muffler design. This not only contributes to the horsepower gain but also sheds significant weight compared to the stock exhaust, which is heavy with multiple resonators and heavy muffler cans. The sound profile is deeper and more aggressive under load yet remains civilized during highway cruising, avoiding the drone common with lesser systems.
Comprehensive Cost Breakdown
Installing the HKS Legamax exhaust involves more than just the price of the hardware. To provide a complete financial picture, we will break down the costs into five distinct categories: the exhaust system itself, professional installation labor, necessary ancillary parts, applicable taxes and fees, and a potential optional cost for ECU tuning to maximize the gains. All prices are based on average market rates in the United States as of late 2024 and may vary by region and vendor.
1. Exhaust System Pricing
The HKS Legamax cat-back exhaust system for the Infiniti Q60 is the single largest expense. Pricing can fluctuate based on the retailer, current promotions, and whether you purchase a full cat-back or an axle-back version. The Legamax is typically sold as a complete cat-back system.
- Retail Price Range: $1,200 - $1,500
- Average Street Price: Approximately $1,350
Major online performance retailers such as Z1 Motorsports and Concept Z Performance are reliable sources for authentic HKS parts. Be wary of significantly cheaper listings on second-hand marketplaces, as incomplete or damaged units can lead to higher overall costs. The system typically includes the mid-pipe, rear muffler section, all necessary clamps, and hardware.
2. Installation Labor Costs
While a skilled DIYer with a lift and proper tools can install a cat-back exhaust in a weekend, most owners opt for professional installation to ensure proper fitment and to avoid tedious work with rusted hardware. Labor costs depend heavily on the shop’s hourly rate and the time required. On the Infiniti Q60, the factory exhaust is a single heavy assembly, but it is accessible from underneath.
- Estimated Labor Hours: 1.5 - 2.5 hours
- Typical Shop Rate: $100 - $150 per hour
- Total Labor Range: $150 - $375
Many independent performance shops and even some Infiniti dealerships will perform this work. Expect to pay on the lower end if you are replacing a factory system. If the original hardware is severely corroded or if the vehicle has a winter climate history, additional time for cutting or torch work may apply. A safe budget estimate for labor is $200.
3. Additional Parts and Hardware
The HKS Legamax system typically comes with new gaskets and clamps, but it is wise to have a few spare parts on hand. The factory exhaust hangers can be reused, but they can be brittle with age. Additionally, if the exhaust is being paired with downpipes or a test pipe, a 3-inch to 2.5-inch adapter may be needed, though this is rare for a cat-back install when mating to the factory catalytic converters.
- Replacement Gaskets (if needed): $15 - $30
- New Hardware (nuts, bolts, springs): $10 - $20
- Silicone Hanger Inserts (for vibration damping): $15 - $25
- Miscellaneous Supplies (penetrating oil, anti-seize): $10 - $15
Total for Additional Parts: $50 - $90
4. Taxes and Shop Fees
Do not overlook the impact of local sales tax and any shop-imposed fees for waste disposal or shop supplies. This varies widely but is a real cost.
- Sales Tax (assuming 8% average): ~$100 - $120
- Shop Environmental Fee: $10 - $25
- Total Estimated Fees: $110 - $145
5. Optional: ECU Tuning
To fully realize the 20 horsepower increase and to correct the air-fuel ratio after a freer-flowing exhaust, an ECU flash or piggyback tune is highly recommended. While the Legamax exhaust alone can provide a noticeable 10-15 horsepower gain at the wheels, the full advertised figure often requires retuning to optimize ignition timing and boost targets for the increased flow. This is not a mandatory cost but should be considered part of the overall investment.
- ECU Tune (Remote Flash): $400 - $800
- Piggyback Tuner (JB4, RaceChip): $500 - $600
Total Estimated Cost for Installation
Combining the core components, we can project the total financial commitment required to install the HKS Legamax exhaust on your Infiniti Q60.
- HKS Legamax Exhaust System: $1,200 - $1,500
- Professional Installation Labor: $150 - $375
- Additional Parts and Hardware: $50 - $90
- Taxes and Shop Fees: $110 - $145
- Subtotal (Without Tune): $1,510 - $2,110
- With Recommended ECU Tune: $1,910 - $2,910
Average Total (Without Tune): Approximately $1,700
Average Total (With Tune): Approximately $2,300
Performance Gains and Tuning Synergy
The advertised 20 horsepower increase is achievable, but it requires the complete system working in concert with the engine management. The HKS Legamax reduces backpressure by over 30% compared to the stock system, allowing the VR30 engine to breathe more freely at higher RPMs. On a dyno, a Q60 with a Legamax exhaust and a quality 93-octane tune from a reputable provider like Sonic Motors or Ecutek typically sees 330-340 wheel horsepower from the factory 300 crank horsepower. This translates to a visceral improvement in acceleration, particularly in the mid-range (3,500-5,500 RPM). The sound improvement is equally important. The Legamax produces a refined, European-inspired growl without the raw, raspy tone of some unsilenced exhausts. It eliminates the factory muffled sound, giving the twin-turbo V6 the voice it deserves.
Installation Process and Considerations
Tools Required
If you are performing the installation yourself, or simply understanding what the shop will do, the process is straightforward. Key tools include a set of metric sockets (10mm, 12mm, 14mm), a breaker bar, penetrating oil, and jack stands with a jack. A lift is highly recommended for safety and ease.
Step-by-Step Overview
- Preparation: Raise the vehicle securely. Apply penetrating oil to all exhaust flange bolts and rubber hangers.
- Remove Factory Exhaust: Unbolt the mid-pipe from the catalytic converters. Unmount the rear muffler assembly from the rubber hangers. The factory system is heavy, so support it during removal.
- Transfer Hardware: The HKS Legamax system uses new hardware. Install the provided gaskets and slip-fit connectors.
- Install New System: Hang the new muffler section onto the factory hangers. Attach the mid-pipe to the muffler section and then to the catalytic converters. Hand-tighten all bolts.
- Align and Torque: Before final tightening, adjust the exhaust tips for perfect centering in the rear bumper cutouts. Torque all main flange bolts to manufacturer specs (approximately 35-40 ft-lbs).
- Test for Leaks: Start the engine and check for any exhaust leaks at the joints. Tighten as needed. A slight condensation from the tips is normal.
Long-Term Maintenance and Wear
A properly installed stainless steel exhaust requires minimal maintenance. Unlike aluminized steel systems, the T304 stainless used by HKS will resist corrosion for the life of the vehicle, even in road-salt-heavy environments. The only regular check should be the condition of the rubber hangers, which can dry out over 5-7 years. Replacing them is inexpensive and prevents the exhaust from sagging. The polished stainless steel tips can be cleaned with a standard metal polish to maintain their appearance.
Comparing the HKS Legamax to Competitors
When budgeting, consider how the HKS Legamax stacks up against other popular Q60 exhausts, such as the AWE Tuning Touring Edition or the Fast Intentions Non-Resonated system. The HKS is priced competitively in the mid-range, offering superior build quality and a sound profile that many find more refined than the aggressive AWE system. While some competitors may be slightly cheaper (around $1,000), they may not offer the same level of drone-free cruising or the weight savings. The Legamax saves roughly 15-20 pounds over the factory exhaust, which is a small but meaningful reduction in unsprung weight.
Warranty and Authenticity
Always verify that you are purchasing an authentic HKS product. Counterfeit exhausts exist and can fail prematurely, leading to higher costs. Authentic HKS products carry a limited lifetime warranty against manufacturing defects. Check with your retailer for warranty details. For more information on HKS warranty policies, visit the official HKS warranty page.
Conclusion
Installing an HKS Legamax exhaust system on your Infiniti Q60 is a high-value performance upgrade that combines a significant power increase, weight reduction, and a premium sound quality. The total project cost ranges from approximately $1,500 for a DIY install without a tune to just over $2,900 for professional installation and a full ECU calibration. When you factor in the improvement in driving enjoyment and the potential for increased resale value on a modified car, the investment is sound for any enthusiast. By budgeting for the system, labor, and parts as outlined above, you can approach this modification with confidence and avoid unexpected expenses. The HKS Legamax exhaust is not just an upgrade; it is a transformation of the Q60 driving experience.