Maybe at 31 I'm getting old, but I've found anything loud to only be cool for a couple days. Flowmaster will be loud all the time, Magnaflow does a better job in my opinion of enhancing the 4.0L rumble without being obnoxious, and no baffles to break inside. Every flowmaster I had on my old Jeeps broke a baffle or rusted out much quicker than I imagined it would, just garbage build quality. I'd stick with stock, the walker Quietflow SS, or if you want a bit more rumble, a Magnaflow muffler with an 18" long case.