I started with the Bennett muffler on my Giant Aeromaster/RCIgn G62 combo, but cut a bigger hole in the cowl and used the production muffler after a few flights because the Bennett was just too loud. The plane does not look too bad with the cowl cut around the standard muffler. Cheap and effective. If you use a Pitts style you will have to rework the firewall area for more clearance.

Plane flies wonderful.