Why dont you just buy a box from ebay for 50 Euro?
99% of the boxes cheats the ECU to believe fuelpressure is lower on the common-rail than it actually is, so ECU asks the high pressure pump to raise the pressure...& hey presto, you got your 20 BHP extra...But NO increased economy as the computer has been chated by a faulse pressure-signal & its this way it calculates the Km/L / L/100Km/MPG...I have formerly used this type of boxes on many different cars & never noticed whether i paid 400 Euro (like i did on the first box back in 2002) or 45 Euro like i did on the last one for my ALfa 159 2.4 Diesel.