Many threads on this topic…try drilled exhaust in the search field. Here’s one of them
www.xr1200ownersgroup.com

Drilled stock exhaust
Hey, do any of you know of a YouTube clip by one of our members of a drilled stock exhaust? I'd really like to hear one before I took a drill to mine. I'm gonna get the SERT for my XR pretty soon but was wondering what a drilled exhaust sounded like. Thanks, Tim.:)