I'd say avoid this car by all means. Unless the price offered by the dealer is way below market price and you're willing to spend a lot of time sending the car for repairs. Perhaps the white smoke mean that its time for a full overhaul , easily 2-3k i guess. And about the mileage, probably it has been tempered by the dealer ( also shows that the dealer isnt honest ). Also , take note that Mazda Lantis parts are getting more scarce unless you know where to source your parts. Parts also isnt exactly cheap. Go survey around for better condition ones, im very sure you can find them.