String Theory Garage will be closed to the public from Wednesday, 29th July to Thursday, 6th August for our annual shutdown.
If you need to get in touch, please leave us a voicemail or send an email. Our team will happily get back to you when we return on Friday, 7th August.
Shopping online? Don't worry! Our online store will remain active! We hope to ship orders placed for in-stock items as normal during the shutdown. Anything else will be dealt with upon our return.
Thank you for your understanding, String Theory Garage Team
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.
