Opinions?

 

The rule of thumb is to use wut ever size outlet your turbo is. Ex: if your turbo had a 2.5" outlet, then you would use 2.5" piping. Anything bigger is suppose to result in more lag. But me personally, I decided to use 2.5" piping because of my FMIC. My turbo outlet is 2.25". With bigger charge piping, or bigger than your turbo outlet, you may get a bit more lag than if you ran the same size as the turbo outlet.

Hope this makes sense.........

 

My turbo outlet is like 1.75" and I'm using 2.5 charge pipes all the way