Currently the best all weather tyres are Goodyear Vector 4 Seasons, but don't know if they do runflats. I don't know why your BMW dealer told you what he did. Probably wants to sell you a fresh BMW winter wheel and tyre package. Tyre sizes are slightly different on F30 3-Series from E90/91s, but I don't see why your wheels and tyres will not fit. Try them. Obviously front wheels first because the front wheels have the biggest brakes.