Definitely worth it, for me . Loopz will make the exhaust significantly louder whether with stock or ANY aftermarket slip-ons. It's surprising how much the cat muffles the exhaust. I have TBR slip-ons and it's pretty loud when you're "gassing" it. Otherwise, it's not annoying and the Loopz take care of drone. I'm a big fan of the Loopz.