RE: GMS .47 engine
I don't have any experience with the TT Pro 46, but I do have 3 of the GMS .47's and all with tuned mufflers.
I like the .47's and have never had any problems with them once they are sealed. Mine are real screamers and they are about the only 2-strokes I use any more.
If you decide to buy one, make sure to get one with the tuned muffler.
Just mho,