Ya it makes a big difference. My buddy just took off the muffler, and his wasn't hardly any different. I took both off, and its alot louder

 

it's a whole lot louder when you're on the go pedal. It's downright loud if you hammer it in and underpass.

 

well I bought some 4" pipe today and the cat will be coming off tomorrow. I would take the muffler off to but I'm afraid it will be to loud. I had a 98 12 valve with the cat and muffler gone and when it was time for a road trip after about 100 miles it started to get old.

 

Loose the cat keep the muffler! Loose the muffler keep the cat!
I guess to add to the performance and lower temps then you would loose the cat & keep the muffler? Or loose the muffler & keep the cat? Not wanting to make things much louder

 

Lose the muffler. Sounds great without it

 

In my case, when the cat fell off, I could tell almost no difference in the sound at all. I could tell an immediate difference in MPG (about .5-.75 MPG) as calculated in my spreadsheet. I do not have guages as of yet so I cannot comment if EGT's were reduced by doing this or not. Do not know what, if any, gains would be netted by the removal of both the cat and muffler as my main goal is the truck being quiet while it works. I have heard some say that they experienced drone after removing some exhaust parts, I have had 0 drone or any other negative effect after doing this.

 

silencer ring removed, and turbo back straight piped. Loud and obnoxious, just how I like it!...

 

I have one of those areo turbine resonators, no cat on the '07 and it sounds awesome. It's not too loud just tooling around empty, but really roars when you get on it. But I would not want to tow much with it - DROOOOOOOOONE big time.

 

maybe a stupid question for here, but what intakes are you guys running? Prices are all over the place for intake systems and like all of you, I want the best bang for the buck. Banks seems the most expensive along with S&B and so on. I have heard if you don't use the "scoop" on these systems, you might as well keep your stock box.

 

PSM or PSM DIY style. It picks up the air right behind the air dam.

 

Yep, get the cold air of the stock box with increased flow..

 

When me and my 20 month old son rolled down the windows and roared out of the muffler shop after the big 12V muff/cat delete, we both laughed and laughed all the way home. For like 2 days I couldn't stop smiling and he couldn't stop making that engine sound with his lips. Everytime I pull up next to one of those 4 banger civics with a 'loud' exhaust I line my pipe up with his open window...give him a taste of his own medicine with a black cloud for dessert!

I absolutely love the sound but after 2 months starting to wonder if I should do something to tone it down slightly as I doubt a cop will find it so funny...on second thought, naaaaa!!