Give it a try before buying new mufflers. I'm currently running a .91 with mavvrik muffler and its no louder (might be quieter) than my weedeater. Over a gallon used in my backyard and no neighbor complaint...yet

On very first start the idle was so quiet it was running before I knew it...the drill I used for a starter was louder than the engine idle! Also when you start forward flight and get a distance a way that first hint of engine failure (no sound) will be priceless in saving your aircraft.

Mike