im looking to buy a used z4m but cant get a grasp of the figures that people are asking.i was 2nd in line last week to buy an m on autotrader,the asking price for the 07 with 15000 mls was £19000 but went for £18400.i put a bid in for an 06 which is up for £23000 but he seems not to want to move that much from the asking price?what do people on here think a fair price would be for ethier an 06/56 or an 07/57?thats a coupe not a roadster.