Done a fari few more miles with this on now (still only about 300) and I thought I'd post up some initial thoughts.
Fuel economy still remains largely unaffected, i'm down about 2mpg on what I'd usually get, but I know my foots been much heavier. I've got about 4.5k of comparison data logged, so we'll where it settles down to in time.
The power is insane, but in a very dieselly way. It isn't going to do amazing 0-60 times as it simply can't get the power down in first or second (third is scrabbly if you floor it at about 30 in the wet). However, thats more than made up for by the fact that third is astonishingly good. 30-70 in third feels like its not too far off my bosses E92 330d, although it runs out breath faster obviously.
Basically it makes me grin, a lot, easily worth the cash.