3SX Performance Guide: Best Mitsubishi 3000GT Upgrades

TL;DR - Key Takeaways

• 3SX Performance is the premier specialist for 3000GT/Stealth platform modifications and parts

• Start with reliability mods (cooling, maintenance items) before chasing power

• Stage your build: bolt-ons first, then supporting mods, finally major engine work

When it comes to building a Mitsubishi 3000GT or Dodge Stealth, 3SX Performance in North Carolina is the name that comes up in every conversation. They've been the go-to specialists for the platform since the 1990s, developing parts, providing expert advice, and performing builds that range from mild street cars to all-out race machines.

Whether you're just getting started with basic modifications or planning a complete engine build like Bryan Petty's upcoming 420-470hp VR4 project, understanding what 3SX offers and how to properly stage your modifications will save you time, money, and frustration.

Why 3SX Performance?

3SX Performance isn't just another parts vendor - they specialize exclusively in the 3000GT and Stealth platform. This focused expertise means they understand the unique challenges these cars present, from the complex twin-turbo system to the tight engine bay packaging. They manufacture many of their own parts, test everything extensively, and provide technical support that generic tuning shops simply can't match.

Real-world examples like the 1993 VR4 build and Max Kaewtong's 1991 VR4 showcase what's possible when you combine quality parts with proper installation and tuning.

Stage 1: Essential Reliability and Maintenance Upgrades

Before adding power, ensure your VR4 or Stealth is mechanically sound. These cars are complex, and neglected maintenance will bite you hard when you start turning up the boost.

Cooling System Upgrades

The twin-turbo 6G72 generates serious heat, and the factory cooling system is marginal at best. 3SX offers comprehensive cooling upgrades that should be priority number one:

Aluminum Radiator: The 3SX aluminum radiator provides significantly better cooling capacity than the factory unit. It's a direct bolt-in replacement that can handle much higher power levels.

Upgraded Intercoolers: The 3SX front-mount intercooler kit dramatically reduces intake air temperatures compared to the factory side-mount setup. Lower intake temps mean more power, better detonation resistance, and more consistent performance. This is exactly what Bryan installed on his build, and it's a must-have for any serious VR4.

Silicone Hose Kits: Replace aging factory rubber hoses with silicone units that won't crack, split, or collapse under pressure. 3SX offers complete kits for coolant, intake, and intercooler piping.

Exhaust System Improvements

Downpipes: The restrictive factory downpipes are a major bottleneck. 3SX high-flow downpipes significantly improve exhaust flow, reduce backpressure, and unlock noticeable power gains even on stock turbos. These were on Bryan's mod list for good reason.

Test Pipes or High-Flow Cats: Replacing the restrictive factory catalytic converters improves flow even further, though check local emissions laws before going this route.

Cat-Back Exhaust: While not as critical as downpipes, a quality cat-back system from manufacturers like HKS (as seen on Bryan's VR4) improves flow and provides that addictive turbo soundtrack.

Fuel System Basics

Upgraded Fuel Pump: The factory fuel pump is adequate for stock power but becomes a limitation with modifications. A Walbro 255lph pump is a common, affordable upgrade that supports 400+ horsepower.

Fuel Pressure Regulator: An adjustable FPR allows you to fine-tune fuel delivery, essential for any power modifications.

Stage 2: Bolt-On Performance Modifications

Once reliability is addressed, these bolt-on modifications provide noticeable performance gains without internal engine work.

Intake System

3SX Intake Kit: A properly designed cold air intake reduces restrictions and lowers intake temperatures. The 3SX kit maintains good filtration while maximizing flow - much better than generic eBay intakes. Many builders also opt for the K&N FIPK as Bryan did.

Boost Control

Manual Boost Controller: The simplest way to safely increase boost pressure on stock turbos. A quality manual boost controller allows you to dial in 15-18 psi (up from factory 11-12 psi) for solid power gains.

Electronic Boost Controller: For more precise control and features like boost-by-gear, an electronic controller like those from GrimmSpeed or Turbosmart offers additional functionality.

Blow-Off Valve Upgrade

While the factory recirculating valve works, an aftermarket BOV like the Greddy unit on Bryan's car provides more positive pressure relief and that satisfying turbo flutter sound between shifts. Just ensure it's properly vented to avoid running rich.

Ignition Upgrades

3SX Coil Packs: Upgraded coil packs provide stronger spark energy, especially important at higher boost levels where cylinder pressures increase.

Quality Spark Plugs: Properly gapped performance plugs (typically one step colder for modified cars) ensure consistent ignition.

Stage 3: Serious Power - Turbo and Engine Upgrades

This is where builds like Bryan's planned 2026 upgrade and the Ralliart-inspired 1992 build come into play. You're looking at significant investment but also serious performance gains.

Turbocharger Upgrades

3SX 16G Turbos: A popular choice for 400-450hp builds, these turbochargers spool quickly while providing substantial power increases over stock. They maintain good street manners while delivering track-worthy performance.

3SX 20G Turbos: For 450-550hp goals, the 20G turbos provide even more top-end power. They require more supporting modifications but deliver serious performance.

TD05 and Larger: Beyond 550hp, you're looking at TD05 or larger turbochargers. These require extensive supporting modifications including fuel system upgrades, standalone ECU, built internals, and professional tuning.

Engine Management

Standalone ECU: For serious power or when modifying turbos, a standalone ECU like AEM Infinity or Haltech is essential. This allows proper tuning for your specific modifications and provides safety features like boost control, launch control, and traction control.

The factory ECU can be tuned for mild modifications, but its limitations become apparent beyond 350-400hp.

Supporting Modifications for Big Power

Larger Fuel Injectors: Stock injectors max out around 350-375hp. Bigger injectors (550cc, 750cc, or larger) are required for higher power levels.

Upgraded Fuel System: High-pressure fuel pumps, larger fuel lines, and potentially a fuel surge tank ensure adequate fuel delivery under all conditions.

Transmission and Clutch: The factory transmission can handle 400-450hp with proper maintenance, but a clutch upgrade becomes mandatory. The Exedy twin-disc is a popular choice for high-power builds.

Built Engine Internals: Beyond 500hp, forged pistons, stronger rods, and upgraded head studs become necessary for reliability.

Suspension and Handling Upgrades

Power means nothing if you can't put it down effectively. As highlighted in our OEM Plus build philosophy article, balancing power with handling creates a more complete package.

Coilover Suspension

KW V3 Coilovers: As featured on Bryan's VR4, these premium dampers offer fully adjustable compression and rebound. They're expensive but worth every penny for serious enthusiasts. Check out our detailed KW V3 review for more information.

3SX Coilover Options: 3SX also offers their own coilover kits at various price points, all designed specifically for the 3000GT platform.

Sway Bars and Chassis Bracing

3SX Sway Bars: Front and rear sway bars reduce body roll and improve turn-in response.

Strut Tower Braces: Front and rear strut tower braces improve chassis rigidity, especially important on aging chassis.

Wheels and Tires

Lightweight forged wheels like the Volk TE37 (as seen on multiple builds including Bryan's) reduce unsprung weight while looking incredible. Pair them with quality performance tires like Continental ExtremeContact Sport for maximum grip.

Braking Upgrades

More power demands better stopping ability:

Stainless Steel Brake Lines: Replace rubber lines with stainless steel for better pedal feel and consistency.

Performance Brake Pads: High-friction pads from manufacturers like Hawk or EBC improve stopping power without requiring expensive big brake kits.

Big Brake Kits: For track use or serious power, consider Brembo or StopTech big brake kits for fade-free stopping power.

Building Your VR4: Recommended Upgrade Path

Budget Build ($3,000-$5,000)

Focus on reliability and mild performance gains:

• 3SX aluminum radiator

• 3SX downpipes

• Boost controller (15-16 psi)

• Quality intake

• Maintenance items (timing belt, fluids, etc.)

Target: 340-360hp with improved reliability

Intermediate Build ($8,000-$12,000)

Significant performance with maintained drivability:

• All budget build items

• 3SX intercooler upgrade

• Fuel pump and pressure regulator

• 3SX 16G turbos

• Standalone ECU with professional tuning

• Upgraded clutch

• Quality coilover suspension

Target: 400-450hp with excellent street manners

Advanced Build ($15,000-$25,000+)

Serious power for dedicated enthusiasts:

• All intermediate build items

• 3SX 20G or larger turbos

• Larger fuel injectors and fuel system upgrades

• Built transmission or sequential gearbox

• Built engine internals (if targeting 500hp+)

• Premium suspension components

• Big brake kit

Target: 500-600hp+ with professional-level performance

Common Mistakes to Avoid

Skipping Reliability Mods: Don't add boost to a car with a questionable cooling system or weak fuel delivery. Fix the foundation first.

Cheap Parts: The 3000GT platform is complex and unforgiving of poor-quality parts. Buy once, cry once with quality components from reputable manufacturers.

Inadequate Tuning: A proper dyno tune by someone experienced with the platform is essential. Remote tunes can work but in-person dyno tuning is always preferable.

Neglecting Maintenance: These cars require diligent maintenance. Regular oil changes, fluid checks, and proactive replacement of wear items will prevent costly failures.

Finding a Good 3000GT/Stealth to Build

Before you start buying parts, make sure you have a solid foundation. Our complete 3000GT VR4 buyers guide covers everything you need to know about finding and purchasing the right car.

As values continue rising (covered in our 90s JDM appreciation article), buying a well-maintained example becomes even more important. Starting with a solid car means more budget for performance upgrades rather than fixing deferred maintenance.

Working with 3SX Performance

Whether you're ordering parts for DIY installation or having 3SX perform the work, their experience is invaluable. They can recommend the right combination of parts for your goals and budget, saving you from costly trial-and-error.

Bryan's planned 2026 engine build through 3SX demonstrates the smart approach - comprehensive planning with all supporting modifications specified upfront, ensuring reliable power delivery at his 420-470hp target.

Conclusion: Build Smart, Build Right

The 3000GT and Stealth platforms offer tremendous performance potential when properly modified. 3SX Performance provides the parts, knowledge, and services to build these cars correctly. Whether you're planning an OEM Plus approach like Bryan's or an all-out performance build, starting with quality parts and professional guidance ensures your VR4 will be reliable, fast, and enjoyable for years to come.

Take inspiration from the builds featured on Stance Auto - Bryan's refined 1996, Max's clean 1991, the modified 1993, and the Ralliart-inspired 1992 - and build your own VR4 legend.

This performance guide is brought to you by Stance Auto Magazine - your source for car builds, modification guides, and automotive culture.

Related Articles

1. Bryan Petty's 1996 Mitsubishi 3000GT VR4 Build: OEM+ Perfection With 320HP - Real-world 3SX upgrades in action

2. Complete 3000GT VR4 Buyers Guide: Finding Your Perfect Twin-Turbo AWD Legend - Find the right foundation for your build

3. Max Kaewtong's 1991 Mitsubishi 3000GT VR4 - First-gen performance build

4. Modifying a Dream Car: 1993 Mitsubishi 3000GT VR4 - Another excellent build example

5. 1992 Mitsubishi 3000GT VR4: A Tribute to Ralliart's Spirit - Rally-inspired modifications

6. OEM Plus Build Philosophy: Enhancing Without Compromising Character - The smart way to modify

7. KW V3 Coilover Review: Worth The Investment - Premium suspension for your VR4

8. 90s Japanese Sports Car Resurgence: Why Values Are Climbing - Investment perspective

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