I don't rubber mount gas engines, even my DA 100 is solid mounted. My old hurricane has a Brison 2.4 now my son has taken over the plane, so I just started a new one with a Brison 3.2. The problem I see with soft mounts is that if they hold a 5 pound motor at 10 G's they are too stiff to be of real use. You will find many however who disagree with this, but in 10 years of flying gas I've never had a problem.