i have an 05 1.8 c, pretty sure its a z18xe mate, never heard of people tuning z18xer's on here so i highly doubt its in any C, best person on here to talk to would be warren G i think, seems to know his stuff about engine conversions.. question is why do you need to know out of interest, if your thinking of tuning its pointless changing to the z18xer for the sake of 15bhp, just tune up a standard z18xe, or stick a turbo on it, better still do a z20let conversion ?