Kind of a reverse idea to what most people are requesting but can you remap a diesel engine, not for speed, but to make it uber-efficient???
I'm particularily thinking about what improvements can be made on my wifes X3. It's a 56 plate 3.0d M Sport (pre-ED model), auto, got caught in the higher road tax bracket due to its emmissions before BMW quickly revised the xdrive model in Sept 2006. It's currently averaging around 27/28mpg (currently 27.1mpg).
I'm purely looking at improving the mpg - what sort of real-life gains do you think are realistic.
Current -: MW E92 M3 Competition Pack / Qashqai+2 Tekna 1.6dci
Gone -: 370Z GT Roadster; BMW X3 3.0d xdrive M Sport; E46 330i M Sport Coupe; Mazda RX8 231; Nissan 350Z GT Roadster; BMW E90 330d M Sport; BMW E92 335i SE; Maserati 4200; Nissan 350Z; Honda S2000; Astra Coupe Turbo; Ford Probe