I've driven the F10 530d and have to say it is a beautiful car to drive. We also have a 30d X6 in thre amily and it is a fine machine and great engine. That said I drove a Porsche Macan during the week which had the 3.0d VW powerplant and I thought it to be a much smoother and petrolesque engine. Would you consider an A8, macan or such? Sacrilegious but I've driven the A8 in particularly extensively and they are amazing cars in every sense.