Its fun to tinker with engines for sure. For 4C engines, remove the muffler, use the breather for tank pressure and you get such a nice 'putt' 'putt' sound. Talking about realism, this is funny. I showed one my my pals the Aerosound unit, it is a sound module that will create the sound of scale engines for EP planes. My pal said this, "You go EP to be silent and now you want to install something to create the sound?" How right he is! We are nuts.