A Personal Journey into JDM Obsession — and the Birth of the Excelsior Z

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IG: @SiegeStyle

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Sacramento, California, isn’t usually the first place people picture when they think of Japanese custom car culture. But sometimes the loudest obsessions are born far from the spotlight—built quietly in bedrooms, garages, and late-night dreams. For Jeff Siegert, it all began the way many real JDM passions start: not in a shop, not at a meet… but in front of a screen.

In 1997, a twelve-year-old kid met Japanese cars through a gray box called the Sony PlayStation. Gran Turismo wasn’t just a racing game—it was an introduction to a new world. Silvia. Skyline. Supra. RX-7. NSX. Names that sounded like legends and shapes that felt like characters. These weren’t “vehicles.” They had identity. They had spirit. They had soul.

And from that moment, Jeff was gone.

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1997–2000: THE SPARK BECOMES AN OBSESSION

What started as a fascination quickly turned into something more profound. In his early teens, Jeff devoured anything JDM-related he could find—import magazines, early internet forums, grainy Japanese street clips, posters of 90s heroes, and model cars hunted down like trophies. If it carried Japanese tuning DNA, he wanted it in his life.

Then, in 1999, another game pushed the obsession into mythology.

The Shutokou Battle series—released stateside as Tokyo Xtreme Racer—did something Gran Turismo couldn’t. It didn’t just show the machines. It introduced the culture around them: the backstories, the nicknames, the underground world of highway racers and personalities carving legends into asphalt. It wasn’t simply “racing.” It was identity. It was personal.

Jeff took that lesson to heart—the idea that a car should feel like an extension of its driver.

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THE FIRST REAL BUILD: COSTUMES FOR CARS

When Jeff got his first real car, a 1993 Nissan 240SX hatchback, there was never a chance it would stay stock.

And here’s where his story gets different.

Jeff wasn’t just into cars—he was also deeply into cosplay. That background taught him something most builders don’t learn early: how to translate imagination into physical form. Fiberglass. ABS plastic. Shaping. Refining. Iteration. The same mindset that created costumes became a new obsession: making “costumes” for cars.

Lips. Splitters. Spoilers. Custom pieces made by hand. That early DIY creativity laid the foundation for everything that came next.

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2016: THE RETURN TO WHAT WAS ALWAYS THERE

Life pulled Jeff away from the scene for a while—education, career development, growing up. He fell in love and married his wife, Saori, and by his late twenties, he had built a stable life.

But stability doesn’t always equal fulfillment.

In 2016, Saori saw something Jeff couldn’t ignore anymore—the feeling that a part of him was still dormant. So she encouraged him to go back and dig up what he loved before life got loud.

At the top of that list, as always:

JDM. Creativity. Building.

So Jeff did what any reasonable human being would do…

He bought a 2007 Nissan 350Z.

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ZAILAS: THE FIRST WIDEBODY — AND THE PROOF

By the time Jeff got into the Z33 platform, the aftermarket was already massive. The easy route would’ve been to order a kit and join the crowd.

But Jeff wasn’t wired that way.

With that revived creative energy—and a refusal to blend in—he began designing and fabricating original aero. By 2018, less than two years into ownership, Jeff had designed and hand-built an original five-piece widebody kit called “Zailas.” Four overfenders. One splitter. A bold, aggressive profile.

Debuting at StanceNation San Jose, the finished car and kit—officially named PZV1—received heavy praise for its presence and originality. What began as one-off art turned into demand, and soon Jeff found himself reproducing the kit in small batches and shipping units across the U.S. and Europe.

For most builders, that would be the peak.

For Jeff, that was the warm-up.

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THE EXCELSIOR: A SIX-YEAR MOUNTAIN

By the end of the 2019 show season, Jeff wanted a new challenge—something more demanding, more detailed, more ambitious.

He stayed with what he knew and loved: the 350Z platform.

And then he started what would become the most intense undertaking of his life:

The PZX “Excelsior” Widebody Kit

A fully transformative reinterpretation of the Z33—so aggressive and layered that the car would become nearly unrecognizable.

This wasn’t a flare-and-splitter kit.

Jeff envisioned a full suit of armor.

The inspiration came from another passion rooted in Japan: mecha and samurai armor design. The goal was to make the Z look like it belonged in a neon Tokyo future—or inside a Gundam hangar. Traditional Japanese aesthetic language translated into modern, sharp-edged automotive form.

He began small: a 1:18-scale model, covered in clay and sculpted by hand. When the idea felt “right,” it moved to the real car—built in a one-car garage in Sacramento.

Then the years began.

Sculpt. Revise. Resculpt. Glass. Reinforce. Refine.
Repeat. Repeat. Repeat.

Perfectionism took over. And the timeline stretched.

Three years passed… and he was only halfway.

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THE SYMMETRY PROBLEM — AND THE FUTURE SAVING THE PAST

The Excelsior design wasn’t subtle. It was layered and complex with intersecting angles, recesses, textures, and aggressive geometry. Mirroring that by hand—perfectly—became the wall.

So Jeff adapted.

He brought in 3D scanning and printing technology to replicate and mirror the opposite side. The tech helped, but it introduced a new set of challenges: unfamiliar materials, parts printed in sections, slow assembly, fitment refinements, and the brutal reality of precision.

Because the Excelsior kit was designed to fit tightly, entire printed sections had to be reworked and rebuilt.

There were nights Jeff wanted to scrap it.

But he couldn’t—not after coming that far.

And by sheer determination, prayer, and a tremendous amount of support from Saori, Jeff completed the full prototype:

31 pieces.

Summer 2025.

Six years of work.

When he finally rolled the car out of the garage fully kitted, he needed a moment to process it.

Thousands of hours. A lifetime of influence. One completed vision.

Staring back at him in the shape of a radically reinvented Z33.

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MAKING IT ROADWORTHY: THE BUILD BECOMES A MACHINE

With the kit complete, the focus shifted to the car itself—because an extreme build that can’t be driven isn’t finished.

The Z was delivered to Sac City Auto, a Nissan specialist in Sacramento, for a complete teardown and rebuild of the engine and running gear. Their team inspected and refreshed nearly everything critical, preparing it for a significant performance leap: the SOHO Motorsports turbo system.

Along the way, the build gained serious supporting upgrades:

• Cusco 6-point roll cage
  
• Upgraded clutch & driveline
  
• Aluminum driveshaft
  
• Stronger 370Z axles and hubs
  
• Chassis bracing, bushings, and handling upgrades
  
• R1 Concepts big brake kit to match the new power

When Sac City finished, the car didn’t just look transformed—it felt transformed. More composed. More confident. More capable in every direction.

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THE FINAL STAGE: SOS CUSTOMZ AND THE COLOR THAT FINISHED THE DREAM

Even after all that work, the Excelsior Z still wasn’t “complete.”

The body was buried under dust and years of primer. The interior had been stripped for a reupholstery plan that never happened. Jeff knew fabrication. He knew design.

But paint and upholstery demanded specialists.

There was only one shop on his radar:

SOS Customz — Oceanside, California

Known for elite paint and interior work on some of the West Coast’s most serious builds, SOS believed in the vision. They took on the project with SEMA in mind.

Eight weeks later, the Excelsior Z emerged wearing the finish it always deserved:

Aston Stirling Green

paired with a fully custom charcoal and gold interior.

Jeff took delivery one week before SEMA.

After six years, the Z was finally whole—just in time for the biggest stage in the world.

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THE EXCELSIOR’S LEGACY

At its core, this build isn’t about trends or flex.

It’s about persistence. Identity. Creativity.
And a lifelong love of Japanese car culture turned into something physical and undeniable.

The Excelsior is proof that the most impactful builds aren’t always bought.
They’re imagined. They’ve suffered through. They’re built slowly.

Piece by piece.

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BUILD SPECS

Engine / Drivetrain

• VQ35HR SOHO Motorsports Top Mount Single Turbo Kit
  
• Garrett GTX3582R w/ Tial 1.03 Housing
  
• 1050cc Injectors
  
• Aeromotive 340 Fuel Pump
  
• SOHO Intercooler + Crash Bar + Solid Engine Mounts
  
• Hypergate 40mm Wastegates, Raceport BOV
  
• SOHO VQ35HR Headers
  
• Tomei Single Exit Exhaust
  
• Full AN coolant/oil lines, PS relocation, catch can system
  

Supporting Performance

• ACT Stage 2 Clutch / Flywheel
  
• Zspeed CSC Elimination Kit
  
• Z1 Aluminum Driveshaft, Z1 Diff Cover
  
• ISR Diff Brace
  
• 370Z Rear Axles/Hubs
  
• Cusco sway bars (front/rear), Cusco strut bar
  
• Voodoo13 Front UCA’s, SPL camber arms, EMU LCA’s
  
• Antigravity Lithium Battery
  

Suspension

• Air Lift Performance 3P
  
• 1/4” lines
  

Brakes / Wheels / Tires

• Work Meister M1 3P 19” (Custom Candy Bronze lips)
  
• Toyo R888R
  
• R1 Concepts 6-pot Front BBK
  
• R1 Concepts 4-pot Rear BBK
  

Interior

• Full custom cockpit upholstery by SOS Customz
  
• Mercury Japan racing buckets
  
• Cusco 5-point harnesses
  
• Sparco L777 wheel + Vertex Evangelion-R limited wheel
  
• Works Bell hub + Rapfix quick release
  
• Coolerworx Pro Shortshifter
  
• Powertune Digital 10” gauge cluster + mount
  
• Nifty City console infotainment screen
  
• OpeliteOptics suede headliner + animated cabin lighting
  
• Cusco 6-point cage (custom powder coat)
  

Exterior

• Custom Paint: Aston Stirling Green
  
• 1 of 1 Prototype PZX “Excelsior” 31-piece widebody kit
   (front/rear bumpers, skirts, fenders, hood, ducktails, wings, garnishes, canards, spats, etc.)
  
• Raysfactory 1850mm carbon GT wing w/ custom bracing
  
• Hyperhive carbon doors
  
• Zakustech carbon louvers (modified)
  
• EPR carbon-powered mirrors + CF handles
  
• Luminous Film tint
  

Lighting

• Fully retrofitted Kouki headlights
  
• Morimoto RGB Bluetooth halos
  
• JDM Kouki clear taillights
  
• Low Glow chasing underglow + custom strobes
  

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WHO BUILT IT

• Design & Fabrication: Jeff Siegert (self-built Excelsior kit)
  
• Mechanical: Sac City Auto (Sacramento, CA)
  
• Paint & Interior: SOS Customz (Oceanside, CA)
  
• Support: Saori Siegert (wife)
  

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SPONSORS / SUPPORT

Sac City Auto • SOHO Motorsports • 742 Marketing • R1 Concepts • SOS Customz • Antigravity Battery • OpeliteOptics • DownStar • Low Glow • Zakustech • Hyperhive • Mishimoto • Raysfactory • Wolfbox • Mazterpiece Automotive • Saori Siegert

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LOOKING AHEAD

Jeff plans continued refinement, selective driving, limited kit production, and future design-driven projects that continue to blur the line between automotive engineering and wearable art.