I have seen the spark arrestor on the quiet core, and just as a spark arrestor itself. I put the quite core on with the spark arrestor tack welded to the end. It worked great for riding, really quieted the beast down. Although, when i went into the swampy mud bog, the screen plugged off and I was unable to get it cleaned by reving the engine up. The result was huge power loss due to the air flow restricion. I was not happy. After I pulled the quiet core out and removed the spark arrestor, I reinstalled the quiet core. Put the end cap back on and fired it back up. It was still quiet but the quiet core was rattleing like carzy. The spark arrestor acts like a spacer to hold in the quiet core. So, I need to take it apart again and put in a spacer, because the rattleing is annoying.