Surely there's a 320D owner hiding somewhere who wants more power in an easily removeable way. This box stand apart from any other box as it plugs into your common rail (as most do) but also into your turbo boost sensor. So it can amend the air intake along with the fuel
Economy wise, on motorway runs doing 70-75mph i got 60-63 mpg. Power wise - see the DTUK website.
Maybe i need to put some pics up...