great advice and i also followed it myself and bought a 530d Sport recently. been very impressed so far. 34mph around town driving normal and as much as 49mpg on a run. £310 fully comp for me and missus to insure as well. great drive, handle well for a big car, and worth searching out a sport if you can imho.
bmwland forum is quite helpful, i'm hoping to get mine remapped shortly after chrimbo.