Hello I am new to the forum I have just purchased a 2011 z4 35is and I need to change the dct oil and plastic sump pan as there is a slight oil leek . Unfortunately I do not know how much dct oil has leaked out as there is no way of knowing without going through the refill process.The gearbox seems to be working ok so far. Do I need to purchase the Ista/d program or is ther another way without it .Any advice much appreciated.