Ok here's a couple of pics which I assume is a straight pipe..
I have a Jones 3030XL I would like to drop in but wanted to check with the experts as to whether that is a straight pipe. I wonder due to the narrowing at both ends....

The truck doesn't seem all that loud with no muffler,but I had the Aero Turbine on my F350 V10 and I really liked the sound.

SO here they are

 

...looks like a really really long resonator. Its a muffler, but with straight pipe characteristics.

 

Just like the old school cherry bombs.

 

aah, so I would remove that and install the Jones.. But now you have me wondering whether it's worth the effort, as that's pretty much what the Jones is as I see it.

 

Yup, looks like a typical muffler shop resonator.
"Straight pipe" is just plain muffler tubing.

 

Yup, Aka glass pack

 

That is what I thought about straight pipe, but it's been a few years since I looked under something that wasn't stock...