The Mazda NB Miata Parts Buyer’s Guide: How to Maintain, Repair, and Restore the Best-Value Roadster of Its Generation

By J & J Auto Wrecking — Edited with technical insights from Car and Driver contributors

For anyone seeking a lightweight, rear-wheel-drive sports car that combines driving purity with mechanical simplicity, the 1999–2005 Mazda NB Miata remains an unbeatable proposition. As the second generation of the world’s most popular roadster, the NB refined the original NA platform, introducing updated styling, improved structural rigidity, larger brakes, and better safety features—all while preserving the driver-centric charm that made the Miata a global icon.

Despite its reputation for reliability, the NB is now a two-decade-old platform. Many examples on the road today require maintenance, repairs, or full restorations. Whether you're replacing a worn-out engine, sourcing an OEM door panel, or searching for a complete drivetrain dropout, understanding the nuances of the NB generation is essential for buying the correct parts.

At J & J Auto Wrecking, we specialize in high-quality, video-tested OEM parts for enthusiast vehicles, including the NB Miata. This guide provides a comprehensive overview of what parts to expect, what to watch for, and where to source the best value when keeping your Miata running at its best.

The NB Miata, produced from 1999 to 2005, continued Mazda’s tradition of accessible sports car engineering. It retained the double-wishbone suspension layout, front-mid engine configuration, and 50:50 weight distribution of its predecessor, while moving to fixed headlights, stiffer chassis bracing, and upgraded electronics.

There were two primary phases within the NB generation: 1999–2000 models (NB1) and 2001–2005 models (NB2). In 2004 and 2005, the Mazdaspeed Miata introduced factory turbocharging and further drivetrain reinforcements.

The NB Miata’s 1.8-liter BP-series engine is a well-engineered, durable unit, but not immune to age. The earlier NB1 used the BP4W engine, with solid lifters, a variable intake control system (VICS), and a more aggressive cam profile. The NB2 introduced the BP6D variant, which included coil-on-plug ignition, revised cylinder head casting, and updated emissions controls. Both variants are rated at approximately 140 horsepower and deliver their power with excellent throttle response and a lively top end. While the BP-series shares many design cues with the earlier NA Miata engines, direct compatibility is limited due to changes in electronics, head design, and accessory layout.

Replacement engine components are among the most in-demand parts in the NB

ecosystem. These include long blocks, cylinder heads, camshaft components, timing covers, manifolds, throttle bodies, and associated sensors. Many NB Miatas also benefit from complete engine dropouts that include the wiring harness, ECU, intake, and transmission. At J & J Auto Wrecking, all NB engine assemblies are thoroughly tested and cataloged with their donor VIN, ensuring buyers know exactly what they’re getting.

When it comes to transmissions, the NB Miata offers three configurations: the standard 5-speed manual, an optional 4-speed automatic, and a 6-speed manual available in later trims and standard on the Mazdaspeed model. The 5-speed is praised for its shift quality and simplicity, and while it shares a basic layout with the NA’s gearbox, there are important updates to internal gearing and shifter linkage.

The 6-speed provides closer ratios and a more aggressive final drive, though it requires a different driveshaft and differential. Enthusiasts seeking to upgrade or repair their drivetrain should pay close attention to transmission codes, shifter tower compatibility, and clutch hydraulics.

Differentials in the NB also vary. Open differentials were standard on base models, while Torsen limited-slip units were fitted to higher trims and the Mazdaspeed. Ratios typically range from 3.9 to 4.3, and some components, like axle stubs and carriers, may differ by application. Replacing or upgrading your Miata’s differential requires matching spline counts and ensuring your axle lengths and mounting points are correct. J & J Auto Wrecking frequently stocks complete NB rear-end assemblies and individual differentials with verified mileage and condition.

NB Miata suspension and brake components see high wear over time, but the platform’s

straightforward layout makes service easy. Double-wishbone suspension arms, upper and lower ball joints, bushings, and shock absorbers are among the most commonly sourced components. ABS was available on many NB models, especially from 2001 onward, and those vehicles use specific knuckles and hub sensors that must be matched carefully. Additionally, front and rear sway bars, end links, and control arms are often upgraded or replaced as part of performance tuning. Factory brake components are also in high demand, with front calipers, master cylinders, ABS modules, and parking brake hardware all available through J & J’s catalog.

Body panels and exterior trim are especially important for NB Miata restorations. Unlike NA models, the NB features a different hood shape, sleeker bumper covers, and integrated projector headlamps. Fender lines and door fitment remain similar, but most panels are generation-specific.

Headlights, taillights, side mirrors, convertible top frames, trunk lids, and rocker panels are all regularly stocked and sold in color-matched condition when available. Our team inspects each body panel for damage, confirms mounting bracket integrity, and provides detailed photos and descriptions for online buyers.

Inside the NB’s cabin, the design is clean and minimal, but seats, consoles, and switches suffer wear after years of use. Dashboards are known for UV damage, especially in warmer climates, and many center consoles crack near the armrest. Power window switches, HVAC controls, gauge clusters, and seat mechanisms are all common replacement items. The NB also introduced dual airbags as standard equipment, so airbag modules and crash sensors must be considered when restoring collision-damaged vehicles. J & J Auto Wrecking maintains a rotating inventory of NB interior parts, from seat sets and steering wheels to entire dash assemblies.

Electronics and wiring deserve special attention when sourcing NB Miata parts. The shift from 1990s analog architecture to early 2000s OBD-II control brought more complexity to engine management, emissions equipment, and diagnostic systems. Early NB1 models (1999–2000) use a different ECU pinout, ignition system, and wiring harness than NB2 models (2001–2005). The 2004–2005 Mazdaspeed Miata introduced an entirely different ECU, wiring configuration, and turbo-specific sensors. Swapping ECUs or sensors across these sub-generations requires exact matches by part number, emissions specification (federal vs. California), and transmission type.

What separates J & J Auto Wrecking from generic suppliers is our experience with enthusiast cars. Every NB Miata engine and transmission is tested on video before sale. Our parts are not just pulled and shelved—they’re inspected, photographed, and tagged with condition notes and compatibility information. We support local and national customers with shipping, technical support, and our unique “Name Your Own Price” tool for select listings.

The NB Miata continues to represent one of the best entry points into performance driving and vintage motoring. Whether you’re keeping a clean example on the road or turning a tired chassis into your next track car, the availability of high-quality OEM parts can make or break your experience. Instead of hunting through unreliable auctions or mismatched aftermarket pieces, rely on a trusted supplier that knows what matters to drivers and restorers.

Search our complete inventory of tested NB Miata parts today. From drivetrain and suspension components to body panels and interior trim, J & J Auto Wrecking has everything you need to keep your 1999–2005 Miata performing like it should.