We have a 123d twin turbo Coupe, and I'd agree about pursuing the diesel option. 150kw and torque to burn.
It's a 2010, with a fair bit of "go faster/stop faster" fluff added, but we found the diesel's a lot more responsive than the similar petrol ones. I do 700km's a week in it, and it hasn't put a foot wrong so far.
However, we are BMW diesel fan's so that could be my bias coming through.
With 3 petrol and 2 diesel BMW's in the fold, I know what is cheaper to run, and we do huge mileages.