what mileage was your 330d on at the time and was it remapped?
Warranty is pointless on this. The biggest possible bill it's likely to throw is either a turbo failure or a gearbox failure.
Both of which can be resolved with reconditioned parts for ~£500.
When the turbo went on my 330d, I did the labour myself, so the total cost was in the region of £350.
Shame its not a sport, what are its details? I like the colour.