Well I've been reluctant to post back on here as I wanted to get the issue resolved but I'm pretty much at the end of the line with it now. After I fitted the unit I went testing. Did about 4-5 laps of the track with the GPA switch set to zero, then he bike started misfiring and running really badly until it died completely. I tried disconnecting the switch but that made no difference. At this point I wasn't sure if it was the new ECU, or an old misfire issue from last season reoccurring. ( this was a blocked injector but continued a bit after it was replaced). I tried a new fuel pump and went back to the track. Same thing happenend exactly. This time I was armed with the standard ECU as well so swapped it out and the back ran perfectly all day..... The GET ECU went back to Italy for tests but they couldn't find anything wrong. They sent me a replacement which I fitted. This time as soon as the bike warmed up it started misfiring, getting dramatically worse when the GPA switch was turned up from zero. It would stall on idle and be reluctant to restart, kicking back violently. I went back again to the suppliers who told me I needed to do a TPS reset on it with a 12v battery. This I've done, system refitted and its no different. Runs ok, then as it warms it starts to miss. Went to restart it and it kicked back so violently my trainer got blown off and hit the ceiling. Maybe on an old BSA I'd expect that but the YZ450 never kicks. So, for whatever reason this system just doesn't like my '10 450. Unless someone has any radical suggestions I'm ready for a refund now. Shame as I can really see the benefits if only I could get the damn thing working. Any ideas? Anyone else bought one and had problems apart from JS? He's advertsing it at the start of the TV coverage for every GP race over here..