My 4000 was loud when I got it, and I changed muffler type and its very quiet now.
My Dexta was noisy, and I bought a Stanley F04 and welded the adapters to it, and applied a rain cap, and it's quiet too. My other Dextas did the same to them. My muffler all have the change of direction baffles, a flat and wide muffler. Still have those old mufflers and the difference is drastic.
Power is the same.