I'm a flowmaster diehard... The muffler will definitely make your truck "louder". But the big echo is from the pipes, that is what makes the truck really loud and gives it that deeper sound. So, if you don't want an echo then don't put big pipes and tips on your truck after you do the muffler.
Like my truck, I put a flowmaster muffler on my truck. Then I put 18" x 3.5" in. tips on my dual pipes and the noise was substantially loud and meaner.... And I also have a 5.4L.
Hope that helps.
2004 Ford F150 FX4
K&N Cold Air Intake System, Flowmaster Dual Exhaust System, 3in Lifted Bilstein Suspension, 35" Hankook Dynapro M/Ts, 17" Mickey Thompson Classic II Wheels and HID 8ks.
Last edited by Regulator; 07-08-2014 at 07:40 PM.