Steve
I am aware that one of the Bear's at Ace lost a stab due to flutter. I realize that it had a 120 2c in it but that should not be a serious stretch in power over the recommended 90 2c. I had a YS-91 in mine turning a 14x7 3-blade, which is just right for the engine. I even took the lower skin off the stabs to make sure the rods were seated and added glue to all the joints. There is a design flaw with the system. Either with the stab attachment or the push rod or both. You should not have to change components from those supplied to make a relaible bird. Especially, when paying that price.
Dan