Describe where you want the difference
A diesel tuning brief might focus on overtaking, pulling through the mid-range or a more progressive response under load. Tell us where the existing car feels limited and whether that behaviour has changed recently. A new loss of performance should be investigated as a fault first.
Peak bhp alone does not describe how the vehicle will drive. Discuss the shape and delivery of torque, the gearbox and your normal operating conditions. An owner doing long motorway journeys may want a different result from a driver regularly towing.
Review the engine and supporting systems
Share the service history, current fault codes and any boost, intake, fuelling or exhaust-system symptoms. Include relevant work already completed. The checks are chosen for the application rather than assuming a clean dashboard means a fully healthy engine.
DPF, EGR, SCR/AdBlue and other emissions-system warnings require an appropriate diagnostic and repair discussion. Performance work is not a substitute for resolving faults, and a road-use tuning brief should account for the fitted emissions systems.
Consider clutch and transmission loading
Describe any clutch slip, vibration, harsh shifts or gearbox warning. Existing mechanical limitations affect the calibration conversation. For supported automatic or DSG applications, we can discuss a combined ECU/TCU enquiry.
A maximum advertised torque number is not an appropriate target for every application. Mileage, maintenance, use and hardware condition belong in the same decision. Tell us if a previous map is already installed.
Use the correct appointment route
The ECU identification and software determine access. Some diesel vehicles have a supported OBD route, while others need bench or specialist procedures. The team confirms the method and practicality of mobile work before scheduling.
Send registration and postcode together with the intended result. Your quote explains the service and agreed checks, including access or additional diagnosis when needed. Economy and power figures remain vehicle-specific expectations, not automatic percentage promises.