Mazda NB Miata Parts Buyer's Guide: Everything You Need to Know

By J & J Auto Wrecking, with technical and editorial insight from Car and Driver contributors

The second-generation Mazda Miata (NB, 1999–2005) remains one of the most widely loved, affordable, and modifiable sports cars on the planet. Whether you’re restoring an early ’99 or upgrading a late production Mazdaspeed NB, sourcing the right OEM parts is key for maintaining reliability, performance, and originality.

At J & J Auto Wrecking, our inventory includes quality inspected NB Miata parts, complete with video verification for engines and dropouts. This guide will help enthusiasts understand NB generation nuances, parts compatibility, and how to buy with confidence.

The NB Miata: Key Features and Generational Updates

Produced from 1999 through 2005, the NB Miata introduced fixed headlights to replace the NA’s popups, retained a lightweight body, and added modern refinements. It featured improved chassis stiffness, larger brakes, optional antilock braking, and a 1.8L BP4W engine with variable intake control system (VICS).

Performance models like the Mazdaspeed turbocharged variant arrived in 2004–05, packing around 170 hp and upgraded drivetrain components.

At J & J, our NB Miata parts collection supports both standard and Mazdaspeed variants from engines and transmissions to body panels, interiors, cooling systems, and electrical components.

1. Engine Assemblies & DropOuts

The 1.8L BP4W I4 engine is the hallmark of NB Miata drivetrains. In 1999–2005 models, Mazda increased compression and revised cam and intake flow, boosting power to about 157 Nm of torque with roughly 104 kW output.

• Our inventory includes 1999–2000 NB 1.8L engine & 5-speed manual trans dropout assemblies, complete with harnesses, clutch master/slave cylinders, and accessories. These are fully inspected, videotested parts available for shipping or pickup.

• Mazdaspeed NB parts (2004–05) use turbocharged BP engines and require specific intercoolers, ECU calibrations, and upgraded fuel hardware.

Compatibility tip: manual transmissions, accessory drives, and harness connectors vary by market (U.S. vs. Japan) and optional stability/ABS systems.

2. Engine Control Module & Electronics

NB Miata ECUs—including manual vs automatic, federal vs California emissions—are generation-specific.

• A typical part: 1999 NB Miata manual transmission ECU (federal emissions, from VIN 105246, harness Bp5x18881a).

• Electronic throttle, sensors, wiring harnesses, and speedometer clusters must match original RPO or VIN-coded configurations.

3. Drivetrain, Transmission, and Differential

5-speed manual transmissions are most common, with an optional 6-speed in late years and Mazdaspeed NB variants.
Parts such as clutch release bearings, shifter mechanisms, and differentials fit only within NB or neighboring NA models and must be matched carefully to year and spec.

4. Suspension, Brakes, and Wheels

NB Miata sees larger ABS-enabled brakes and upgraded hubs compared to NA. OEM bushings, shock towers, and sway bars significantly affect handling behavior.
Our parts include tested OEM suspension arms, spindle assemblies, brake calipers, lines, and hardware compatible with NB models.

5. Body Panels & Exterior Components

Fixed headlamps, fog lamps (standard post 2001), updated front and rear bumpers, convertible top bowls, doors, and softtop frames define NB exterior compatibility.
At J & J, we stock:

• Factory bumpers and fenders with original paint codes

• Headlamp assemblies, grille pieces, and turn signal units

• Convertible tops and rear glass panels

6. Interior and Trim

NB interiors feature revised dashboards, instrument clusters, seat designs (optional leather), and center consoles.
Products in our inventory include:

• OEM door panels and dashboard pieces

• Speedometer clusters for manual transmissions

• Seat sets and trim components with factory stitching

Parts Compatibility & Fitment Considerations

Many NB components share NA origins, but don't assume interchangeability. Year-specific updates such as ABS wiring harnesses, ECU differences, and emission adaptations influence fitment.
Always match RPO codes, catalytic converter systems (federal vs California), VIN-based harness and ECU variations, and mechanical options like ABS or stability control.

Why Buy NB Miata Parts from J & J Auto Wrecking?

We’re the Enthusiast’s Choice for Miata restoration and performance needs:

• Quality inspected, video tested parts for engines, transmissions, and electronics

• Comprehensive NB Miata categories: from drivetrain and suspension to interior, electrical, and body

• Detailed product listings showing item condition, donor VIN, and part compatibility

• Competitive pricing with Name-Your-Own-Price feature available

• Expert support from our team in Marshallville, OH, serving customers nationwide

How to Shop & Connect Article to Product Listings

Throughout this guide, each engine or component section should include internal links to your listings:

• “Shop our 1999–2000 NB Miata 1.8L engine & 5-speed manual trans dropout video”

• “New in stock: 1999 NB Miata manual ECU harness assembly”

• “Browse tested brake calipers and suspension arms for NB Miata from stock #SXMA…”

Ensure each internal link matches the product title and includes keywords like “NB Miata OEM parts,” “tested Miata engine,” and “1999 NB Miata ECU.”

Final Thoughts

Whether you're restoring a classic 1999 NB or upgrading a 2005 Mazdaspeed, understanding generation-specific nuances ensures you source the right parts. J & J Auto Wrecking provides not only a wide selection of NB Miata components but also the testing and technical support to guarantee fitment and performance.
Search our NB Miata inventory online now or contact our tunersavvy team to help locate the perfect parts for your Miata project.