The 420d 163 HP engine is a factory detuned version of the 420d 184 HP engine.
DPF Removal EGR Removal Speed Limit Removal Gearbox Update Fault Code Delete TerraClean
The 420d 163 HP engine is a factory detuned version of the 420d 184 HP engine. Therefore both engines will tune to the same power and torque specification.