Welcome Bill! Better to join than lurk eh.
Great car - obviously
Sorry can't offer any advice re. the white powder as mine doesn't do this. Presumably this powder is entering the cabin when the air con. is in use? Could it be the gas reacting with the aluminium in the air con. system? Just a thought.
All I've had is a sticking headlight wash cover and the drivers door needs 'nipping up' a bit.
Like Chris (cd) has said, keep on at them and let us know the outcome.