I would actually say the opposite was true after my high flows were installed, with exception to the cold start. It sounds like all hells breaking loose when I fire it up in the morning, even more so on an 85+ degree day when I head out to lunch. After it's warmed up it's deep and throaty. If I step on it, it's real smooth sounding. This is all of course my in cab perspective. I would like to hear it from the outside, but I'm awful about letting others drive my vehicles. I tried to have my girlfriend do it, but she said it scares her when she steps on the gas too hard, so I never heard anything more than about 2500 rpms

 

Yeah, my 2010 with stock cats sounds very similar to what I heard with the earlier trucks with hi-flow cats volume wise, but it does sound more "clear" to me.

With regards to "smoothness, it's tough for me to really comment. The Pack is definitely "smooth" sounding after it warms up, sounds awesome, but I have to compare it to the XR-1 and the Corsa system. lol

 

going from an 8" body Cherry bomb to the 14"magnapack.... smooth