P0757 Solenoid B - Too high pressure

IIRC, this should be causing the gearbox to shift only odd gears 1-3-5-7? (or could be opposite).

your friend might get a more accurate diagnosis with a DEIS than a generic OBD reader, it will be most likely the same solenoid but with better detail, it may even be something else happening that is triggering this code. Best to know for sure.

the Getrag DCT is repairable, but my understanding is that the internal replacement parts at this point are only available to certified DCT repair techs, which I believe are still limited to Ferrari dealers - hence the part is not "available to you".

MB uses the same gearbox in their cars, that might be another source, but I would imagine they have similar policies.

Unless you are very comfortable disassembling, diagnosing and repairing a DCT, if the part in fact does need to be replaced, I think you are looking at having a dealer repair.

One of my teammates had this error (or a similar one), the total repair cost was $3-4K. In years past, repair parts/kits and training was unavailable hence required a gearbox swap.