The String Theory Garage Stage 1 ECU map for the Toyota GR Yaris Gen 1 — developed in-house on our own GR Yaris over countless hours of rolling road time and extensive real-world testing. This is not an off-the-shelf generic tune; it's a calibration built and validated by people who daily drive and track the same car.
Stage 1 is suitable for a stock GR Yaris with no hardware modifications, or paired with a performance intake and/or OPF delete. Gains are typically 30–40bhp and 60–80Nm over standard, delivering a transformed mid-range and a far more responsive throttle.
Key features
Developed on STG's own GR Yaris — real-world and rolling road validated
Optimised for UK 98 RON pump fuel
Enhanced boost curve, fuelling, and ignition timing
Compatible with standard hardware or intake/OPF delete
Retains all OEM safety strategies
Remote map delivery available
Typical gains (Stage 1, 98 RON)
Power: +30–40 bhp over standard
Torque: +60–80 Nm over standard
Fitment
Make: Toyota
Model: GR Yaris
Generation: Gen 1
Engine: G16E-GTS 1.6T
Year range: 2020–2024
Variants: All (including Circuit Pack)
What's included
STG Stage 1 ECU calibration file
Remote flash delivery via OBD port (requires compatible tool) or in-person at STG workshop
Post-map support from the STG team
Installation
Difficulty: Workshop required. Map is delivered remotely or in-person — contact us to discuss your preferred method before purchasing.
