Mine came with an MBRP tip on it, but since it is all straight pipe underneath, there is no telling if it is just a tip, or a whole package. With the straight pipe, my 6.0 is crazy loud, like jet engine loud! I am actually looking at having a straight through muffler put on it to tame it down a little...

 

I don't remember if the instructions showed use of a cat option or not. I'm sure they have a kit with that option though.

 

I have had my MBRP for years now and using band clamps and employing different delete options I can run cat delete, muff delete, or both. Currently I am running muff delete (had to go in for emissions, oops) and I have never had a problem with the sound. Also, since I went with T-304 SS I don't ever expect to have any problems.
I also have multiple tips so I can use whatever matches my mood. Crazy...

 

i used the much cheaper 4" afe kit and put on the nicer mbrp tip. have my cat gutted and welded around the pipe. idling it whistles a fair bit and sounds good, anything over 2500 is outright roar! i find that 4" single exit kits whistle more and 4" dual exits have more of the V8 rumble. 5" kits start to drone

 

I am getting ready to install a Flo Pro in the next couple days. Check out YouTube videos for the sounds of the exhausts. That's what I did and for the sound and the price I went with Flo Pro. They have pretty good reviews and the ease of installation is good.

 

I just installed the Magnaflow 4" pipes along with the AeroTurbine 4040XL muffler. It is a little louder at idle but seems pretty decent on the road. Will take it on a road trip this weekend and will see how it will work out. Amazing how much more power I have in the 1200-1500 RPM range.

 

I have the MBRP 4" SS Turbo back system with the cat delete option. I installed it myself and it was easy to do right in the garage. The muffler that came in the kit is a straight thru design so it has good flow. I kept the cat in case Florida goes back to inspecting vehicles, but hopefully that won't happen in my lifetime.

At idle and low rpms it is not bad at all. At higher rpms you can tell the difference in noise over stock, but not terrible.

 

I had the MBRP on my 04 6.0L and loved it! It wasn't overly loud with normal driving, but as soon as you mashed the pedal the turbo started to whistle and the truck bellowed. How I miss my Excursion.