Originally Posted By dannysbee
For a street car I like 3" from the headers to the mufflers and 2.5 tailpipes. It will flow nearly as good as a full 3" system but will not be nearly as obnoxious.

I ran that combination on my Challenger when it was going 11.0s. It was frequently the quieter of two cars going down the track, even when it was the faster car, too.

I did upgrade to a full 3" system when the car started going about 1/2 second quicker. However, it's nowhere as subtle from a noise perspective with the bigger pipes.