It will need remapped if you've changed fuel pressure. emphasis on NEED, dont be surprised if it melts itself very shortly if you dont get it sorted. secondly there is no right or exacting advise on fuel pressure. your fuel pressure and injectors should be fitted, set and then mapped from that, i find stock pressure and regulator perfectly fine so long as you have decent management. obviously running way to much or too little fuel pressure would be stupid, 2.6-3.5bar usually does most folk. Phil