I have a G75 ST and it seems like it needs to be shimmed slightly. I phoned tigre engines in the UK and he said that it was too much nitro. I was using 10% Supaglow then moved to 5% it improved but still not right even with a cool firepower plug. So I ordered the Super Tigre cool plug and a gasket for the head to add on. Also went to my local club where I seen another engine the same having the same trouble that engines bearings let go. But I was wondering if you guys could tell me where to get the shims from as tigre engines said the don't do them just the head gasket.