I took pics of the inside of the stock mufflers. It appears to be similar to the Dynomax Turbo mufflers except it uses slats to diffuse the exhaust gases through perhaps 3 pipes total.

People said they could hear the exhaust from inside their cars while I passed them on the road.

 

No pics Metro! but from what could see from the set I have on my car! theres no slats! very low restriction! tube perforation! hard to tell !

 

How are the GTA mufflers constructed? Does it use regular perforations inside the tubes?

 

looks like possible vented sleeve around tube ?

 

Here's a pic of my stock muffler (RH/passenger side):

 

Funny, I did something similar when I was curious about the construction. I placed a Maglight inside one end and looked out the other. Stock mufflers had no significant light come out the other side. The GTAs had all the light come through with an offset. These mufflers have a pipe come into a chamber and then there is another pipe offset from the input that goes out to the rear. Next best thing to straight through, just with a chamber. Should be very low restriction, but the chamber gives it an older mellow sound.

 

You must be bored with nothing else to do. Do you give colonoscopys too? LOL

 

I was curious about the stock exhaust setup
My 2000 Crown Vic (Magnaflow high flow cats, Ultra Flo mufflers) sounds louder and rowdier than the GT though