I've been searching but didn't found what Im looking for(mostly RB systems).
I got a s4 na with a straight pipe to a single can, with no cats. Its really loud
but I want to run duals and my question is if duals are quieter? I have 2" pipe now and am planing to replace with 2.5" with duals. Or will the duals be even more loud? Just to point out Im using the air pump to run my 5/6 ports.
So what you guys think single vs duals in terms of sound loundness?

 

nothing?

 

Duals will be quieter. The Racing Beat systems sound really good and are barely louder than stock at cruising speeds. You could probably find a used RB catback system for a decent price. If you are going to make a custom system, the main pipe should be 2.5" then split off into 2" pipes.

 

i'd probably agree with that^

what i have noticed is my dual is louder at a lower pitch noise (i'm running dual trust's with cat at 2.5), prolly louder than most that i have heard with other duals in the area i live... I know of others that are running singles straight pipe. I've notice that the're are more louder at a higher pitch. Just depends man....