I noticed that my S-pipe that I bought off the board is 3 inch outter-diameter and I was wondering if there really is much flow difference between the 3" ID vs. OD? I would think that it isn't really much at all but you never know!

 

Not much unless your piping is an inch thick.

How do you like the GS-D3's? I hope to have some soon.

-Dustin-