I had no problem with my avistar tank, flew it for over a year and then sold it. Mine was the ARF version, not the ready to fly version with the radio, etc. Used 5 different engines on it, each with its own vibration characteristics (became the engine break in plane because of its flight characteristics). All of them used the stock tank. I wrapped mine in foam, and used a small piece of balsa spanning the fuse at the rear of the tank to keep it from sliding back (foam padded as well). I didnt use the SIG foam, I just used some packing foam that we had at work from a parts shipment.

Hope this helps,

Steve