Originally Posted by shiv@vishnu
The restriction is from the high density catalysts, not from pipe diameter. And since we are talking about a turbo that flows a maximum of 360-370whp on a good day, extra inlet large ID isn't required.
As for n54 (dual) downpipes, the notion that 3" pipes will outperform 2.5"pipes is funny considering each downpipe only needs to channel half the exhaust flow. But the idea of "bigger is always better" sells to those who don't know any better.
So do you prefer 2.5"? Or does diameter not matter at all to you?