Temps are way too high for a 15min drive. Gearbox temp even more so, considering it doesn't heat up nearly as fast as the engine. For gearbox 85°C is of the highest I've seen and that's after several runs at 25-28°C ambient. For the engine I've seen 105°C again after several runs (spirited driving would be an understatement), but it only takes a few minutes of normal driving to drop back down to about 92°C. Our oil cooling system (cooler and whatever else is involved) is impressive, it's one of the things I'm mostly impressed with. If yours is failing, might explain why it's going into limp mode. How long does it take for the engine to cool back down to let's say 90°C?
So are the high temps the culprit of losing turbo power?