Thinkin about strait pipin my F250 w/ 3.5DP and 4" to infront of rear tire, how much louder is it going to be over a 18-24" magnaflow 4" muffler??

 

At a steady speed, especially with the windows up, you won't notice much difference in volume at all. When accelerating, you'll be making a lot more noise, and you'll hear a lot more flutter. Some like that, some don't.
I couldn't handle the flutter, so I went back to a muffler on mine to tone it down.

 

My 97 is strait piped and there is littel flutter. A friend of my has an 02 and he has flutter big time.

 

I have a 99 with the same setup. It is a little louder then my old 97 with the straight pipe. Also in cold weather you will hear the warm up bypass valve on the turbo alot more. Kinda sounds like a jake brake.

 

The thing will sound like a Helicopter taking off. The new 6.0's are the best sounding thing on the road with a high flow exhaust!! Big block with a jet engine whistle! WOW....my 2.

Dan "Mudinford" MacDonald