Yeah...that's what i had with my 4" muffler deleted. LOUD turbine whistle AND loud flutter. When i put the Aero unit on it killed my turbine whistle and flutter about 70% although i can hear it at the tailpipe...just not reflecting off everything. Thanks for the feedback!
Nut

 

I hope you don't get laid off! The sound is nice but, it's not necessary...at least for me. There's always tomorrow. It's worth the wait. Save your money.

 

The flutter's from the fins on the the turbine (exhaust) wheel chopping up the exhaust gasses as they pass through... or so I'm told. Just the nature of the beast. Any form of straight pipe and you'll hear it.

My exhaust is just the stock size 3.5" but straight piped... man oh man do I love the sound. When it first barks to life when you start it; when the ebpv closes and it just howls; when I'm coasting along through a neighborhood or at slower speeds and the whistle is just SO pronounced; when I get on it on an on ramp and hear it just ROAR... and of course I have to drive around with my rear passenger window down at all times.

On Easter I was driving to my aunt's house for our family get-together, and as I made a left turn into her neighborhood and slowed for another left as soon as I got in there, I see a fella out in his yard washing his Superduty. Well, I just ever so gently roll along through and speed up just a tad as I go through the turn, and that turbo just whistles so loud through the straight pipe... his head snapped to attention and I watched his eyes in my mirror as he stared after me the whole way down the street, until I made another turn again gently cruised along. He just stood there with his sponge in his hand dripping on the ground, his attention completely focused on my truck. It was great.

And I never get enough of cruising through our neighborhood or a parking lot and seeing EVERY head look up when I'm still a long ways away. It never gets old....

 

i got marks 5 inch on my truck and i get alot of compliments on having a cannon back there and as for the way it sounds i LOVE it not much louder then stock till you mash on the pedal then its just music to my ears