RCU Forums - ST 2500-2000 inverted muffler

"Best" will probably depend on a number of factors - such as how much space there is, will you need to modify the structure to make it fit, how much noise can you tolerate and so forth.

I've run the ST2500 upright, almost fully exposed, in a bipe with the old round, black, tin can ST muffler with no problems. It seemed fairly quiet. I've also run it side mounted, tightly cowled, in a bipe with the Super Tigre pitts style muffler. Again, no problems and good noise level.

Now it's going inverted with a Slimline wrap around Pitts style smoker muffler. That did not fit the model so the entire front end had to be redesigned and built differently. Now it fits fine except for the smoke hose connection, which just clears the fuselage side. It's a fairly big muffler so maybe that, along with being inside the cowl will help keep the noise down, unless the fuselage acts like a big sound box and amplifies the noise.

I've also run an OS 1.08 inverted with what Slimline, then called an in-cowl sport scale muffler. Really that was only an exhaust diverter which happened to fit inside the cowl. From that standpoint it did the job but it was a slightly noisey installation.