I have two Saito 2.20 engines. One I have been flying for 9 years. The last 6 in a Balsa USA DVII, and the other has only one season of flights. When I am flying my Saito and a gasser is in the air, I can't hear the 2.20. The 2.20 is a lot quieter. I pulled the one season motor and sold the airframe. Let me know if you want it. Here is my 2.20 in a flight. pretty quiet.
https://www.youtube.com/watch?v=6VQKq0JJyCE