What operators usually want
Low-down torque so the van pulls away loaded without labouring, steadier delivery on motorway climbs, and throttle response that makes junctions less of a wait. Rarely anything to do with peak output.
Why vans have to be assessed individually
Commercial vehicles have wildly different duty cycles. Two identical vans can have completely different clutch, turbocharger and emissions-system condition depending on load, route and driver.
So suitability is decided per vehicle, not per model.
Payload, weights and fuel
A remap does not change legal payload, gross vehicle weight or towing limits. It also does not come with a guaranteed fuel saving — consumption depends on load, route, driving style and conditions.
Downtime
Because the service is mobile, the van can be worked on at a yard, depot or driveway rather than sitting at a workshop during a working day.