No gasoline engine on pipe will "sound like a gas engine". But the soft mount plays a major role. The sound is much mellower and much much quieter, very similar to the larger 2 stroke glow engines we were running on pipe.

Any sport flier or IMAC'er for that matter could soft mount his loud gas set-up and put a pipe on it for very neighborly performance. The complete package includes higher pitched props too.

In regard to soft mounting, the only mount in my opinion that truly attenuates the best is the HYde style mount. I've never owned an original Hyde but have made my own (very similar to Merles') for more than a decade. I have a thread here in RCU that describes exactly how I make mine for stand off mounting. I've made a couple small but important refinements since I posted that thread. The most important refinement was adding rubber bumpers between the two discs to avoid the slapping of the disc faces against one another that one hears are idle. A less important refinement was elimination of blind nuts to support the studs on the front disc. I simply drill and tap an aircraft ply block and install the stud through it and the the ply face. The threaded studs are glued in place. This has reduced weight by 15%

My mount for the 33GT weighs in at a scant 2.5 ozs. Don't know what the Hydes weigh

BTW- I have no interest in making soft mounts for others, at least not until retirement, so please don't even ask me. I am open to answering questions tho. If you don't want to tackle a build yourself, I suggest you contact Merle as Choijin has done.