MSM owners note the factory ECU holds the turbo engine back, with real gains needing an aftermarket ECU, bigger injectors and a tune; the widely-cited reliable sweet spot on stock internals is around 200-215 hp, often via the Flyin' Miata 'Little Enchilada' kit.
MSM power ceiling: stock ECU limits it, ~200hp is the mod sweet spot
Mazda MX-5 Miata (NB) · mechanical