How much power bhp/lb is lost using 95 ron instead of 97/99 ron.

dont know figures but i imagine a fair chunk. once remapped the car takes advantage of the extra ron, the ecu would have to pull back.

tuner would know.

there was a poster on here a couple of weeks ago complaining of poor power few weeks after getting mapped, he had switched to 95 and the power came back when he put the higher rated fuel in. so it must be noticable