Sorry to hijack the thread, I've managed to curb an alloy after owning the car for a week. Is a full diamond cut the best option? Does powder coating offer much more protection?
A powder coated finish is more durable than a diamond cut finish, especially if the car is used as a daily driver; diamond cut wheels when subjected to salt and the roads during the winter months often succumb to white worm corrosion. However, as said, powder coating won’t offer any more protection against kerbing.
Whether you get that single wheel refurbished in the existing diamond cut finish or all four wheels powder coated, I’d certainly consider fitting some better tyres that have good rim protection. It’d also give you a good reason to get rid of those budget Chinese Jinyu (ditchfinder) tyres that have been fitted on your car - IMO not the best tyre to have on a Golf GTI Performance.