2006 R6 Exhaust Bangs?

Hello! One month ago, I bought a 2006 R6. It had a sports exhaust with which it had a very nice sound. I took out the catalyst and there was also a muffler in the center drum, but the db killer is inside the end. I love the sound it makes, the flames and bangs but I'm afraid it's not good for the engine. My question is how bad is this for the engine and should I be worried about it.