Sounds like a plan. Their diagnostics should pick up if any faults were logged. Would normally expect the engine light to come on the dash when that happens but if faults gone will go back out. Quality of fuel maybe or water in the fuel tank.
I know with mine until the car is warm i have boost cut kick in stopping me use full power but feature of upping the boost to protect the DSG box until its fully ready.
What part of rev range? When changing gears?

Hopefully something simple and covered by warranty.