Many aftermarket components require additional data logging and calibration adjustments in order to achieve maximum performance and avoid undesirable driveability issues. The Custom Tune Update option provides additional data logging review and calibration optimization to support common modifications that you installed after receiving your initial Tuning software. Many common modifications are covered under this tune update. More complex upgrades such as larger turbos, fuel injectors, methanol/water injection systems or ethanol flex fuel upgrades may cost additional depending on the complexity of the tuning and if you purchased specific hardware from Vermont Tuning or elsewhere. You must already own our handheld tuning system to order this Custom Tune Update. Please contact support if you have any questions or if you are requesting an update for hardware you did not purchase from our website so we can discuss any additional information we need and the cost for your custom tune update.