U-bend delete you'll need to take it to an exhaust shop because they mess with the 02 sensor, it's not very expensive, just depends what exhaust shop you go to anywhere from $50-$70 I would say. Cowboybought theentire catback system from Dynomax, I just replaced my mufflers for now, but am going to Magnaflow catback in the summer. Themain differances in Dynomax and Flowmaster is, Dynomax is a pretty quiet muffler, just a low kind of quiet rumble as of Flowmaster it's quite loud. At idle you can hear it rumble, low and deep, and when you get on it, you can really hear it. I have Delta Flow 40's, suppose to make it quieter in cabin than the Super 40's. It does some but not all, but I love the sound of my car. I've hadFlowmaster's on all my cars and have loved the sound everytime.