I just spoke with Heliproz and they said that the muffler on every Heli should have a smaller flange opening than the engine's output flange. This is because the engine needs back pressure in order to operate correctly. Not sure if this includes pipes though.
He also said the "pool of goo" is only present after the engine is shut off when the excess fuel drains from the cylinder.
Lastly, he said that the MVPV0102 does not need an additional gasket. Only the metal one that comes with it. No RTV, no paper, only the metal one. I guess the metal gasket is made of soft aluminum that seals upon compression.
Does this all sound correct ? Thanks