ORIGINAL: dubd
You do not need the outer pipe and the 1/16 movement is not a problem. I have a Tam pipe in my Ultra Flash and it works fine. The only challenge is balancing the plane. Since the Tam pipe is lighter, you may need to move your batteries back. I have my smoke pump and 4 batteries under the cockpit area for balance.
I suspect that the pipe will have much more than 1/16th movement if I remove the original outer pipe. Frankly I can not see the benefit of installing this pipe anyway, if it requires major reconstruction it is simply not worth it.
I await additional input from other Tam Pipe users.
I would install the drywall screws as suggested but the owner would frown upon them most vigorously!