Lemans and stone ecus are 15M, but the chip is printed differently. I've looked at the maps for both. In addition to some fueling differences, the ignition initial and full advance is also different. FWIW, I had a severe rough spot at about 2800 - 3200 rpm and some bad behavior on abrupt roll-off with the cali (stone) ecu in my hydro. It was suggested that the ecu was the culprit, so I swapped it for the lemans-labeled one (there is a guzzi sticker over the marelli sticker saying it's a lemans/cali/sport/whatever) and the problem became manageable. Not completely gone, but manageable.