X5M (F95)
S63

Because BMW left obvious headroom in the second-generation S63. The same engine sits in the M5 and M8, and in the X5 M it runs well within itself, so calibration alone lifts a Competition from 617 bhp and 750 Nm to 680 bhp and 850 Nm with the character intact and nothing mechanical altered.

It informs it. A big SUV loads its engine, gearbox and cooling differently to a saloon, and the torque delivery in the file reflects that rather than copying an M5 curve across. The outputs at each stage are the same as the saloon's because the engines are identical; the delivery is the X5 M's own.

The F95 has the highest ceiling of any S63 car Samuel tunes, around 1,200 bhp, but reaching it means a full big-turbo conversion: full-frame turbochargers, downpipes, intakes and serious supporting fuelling. These are one-off projects quoted individually, with the calibration developed around the complete specification you submit.

F95s ship locked, and the V8 uses a pair of DMEs, so the unlock is performed on both, once, before your first calibration is loaded. It is a single upfront step rather than a recurring cost, and it leaves everything about how the car starts, runs and services exactly as normal.

The honest answer: if a dealer links a failure to tuning they can decline that claim, so owners weigh it themselves. Samuel's side of the bargain is calibrating conservatively relative to the hardware's limits and preserving the factory file, so the X5 M can present standard software before any warranty visit.