The ND's Skyactiv-G is a modern, direct-injected engine, so tuning is a reflash game, not a carbureted free-for-all. A header plus an ECU flash is the meaningful N/A combo; a tune alone gives only modest gains.
The 2.0 ND2 in particular is a willing engine, but the factory calibration leaves some on the table, and the biggest restriction is exhaust flow off the head.
- Header + tune is the real N/A move. Freeing exhaust flow and then recalibrating is where the ND wakes up. A tune by itself nets modest gains; the header lets the tune do more.
- Reflash, not piggyback. Tools like VersaTuner and EcuTek are true reflashes that keep the factory safety features. This is the clean, well-supported path for Skyactiv.
- Intake and cat-back add sound and small gains, same story as older cars: do them for character, not big numbers.
- Reliability: Sensible N/A reflashes on the 2.0 are well-proven. Direct injection can bring intake-valve carbon over the long haul; keep up with maintenance.
Going further on an ND:
- Forced induction exists (supercharger and turbo kits for the 2.0), and the Skyactiv responds very well to boost with proper tuning. This is where the big ND power lives, and again, a real tune is mandatory.
- Fuel-system limits matter on the DI engines at higher power; that's part of what serious boosted ND builds address.
Guidance: for a street ND, a header and a quality reflash is the honest sweet spot for N/A. If you want a real jump in power, the ND rewards boost like every Miata before it, just plan the tune and supporting mods as part of the package rather than bolting on and hoping.