Here are the figures, look on hdi tuning post for links to websites etc. It costs in the region of £360 to get the work done. Ive been trying to contact Celtc tuning, they were good at the start but now no reply, wondering if they are on hols. As far as I am aware you dont need any uprated engine parts. Its a straight laptop plug in, change the ecu parameters ( all within design limitations) to the new set up and off you go! I know wozza said try angeltuning but they want me to remove the ecu and send it to scotland, not keen! Will keep trying, I will get it done within the next couple of months and let you all know the outcome. Citroen C4 2.0 petrol VTS Standard bhp 180 upto 192ish petrol not as easy to do a remap on for big power hikes, dont know why Citroen C4 2.0 HDI standard (bhp) 136 upto 180 standard torque (Nm) 320 upto 430 Citroen C4 1.6 HDI (euro III) standard (bhp) 110 upto 136 standard torque (Nm) 240 upto 290 NEW - Citroen C4 1.6 HDI (euro IV) standard (bhp) 90 up to 115 standard torque (Nm) 215 up to 270 Sammy