The Audi A4 1.9 TDI (B6) Turbo Upgrade ECU tuning files are created by a team of experts and car enthusiasts who have been working in this field for many years. They have dyno tested the Audi A4 1.9 TDI (B6) Turbo Upgrade ECU tuning files to ensure that they are high quality and increase power up to 20% while maintaining the best fuel efficiency.