I finally got a reply from the people at Goldberg, but it wasn't really helpful at all.
"We have never tried a gas engine in the Obsession. Good Luck. The fuselage has no hole for a tune pipe but modelers have called us that have put a pipe in."
All I know is that time is running out on the $25 off at Tower, and I still don't know whether I'm going to buy the Obsession 3D, or the FuntanaX 100 for my MVVS 1.60? [

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