Playing Ott Tanak a bit too much?
We never got the Mk6 Fiesta ST150 here in the states, but maybe some of the UK/Euro members on here can respond with an answer/suggestion.
I do know that IF the rules for the class allow it, people prepping Mk7 Fiestas (1.0 Ecoboost, ST, or otherwise) for gravel rallying here in the states will upgrade the half shafts if they can.