I currently have a BMW 3 Series 3.0 E90 diesel automatic with 105,000 miles on the clock. Should I replace it because it's a diesel? I'm interested in an BMW M135i but currently cover around 15,000 miles per year. Would this be a good buy (I'd miss the torque and sound of a six cylinder so ideally want a 3.0-litre alternative)? Would this mileage justify a petrol over a diesel or should I opt for a newer diesel BMW 3 Series 3.0 F30?