Outer Limits 4x4 Board

Picked up a 3" off a mate yesterday for my gu. It only starts after the first 90 degree bend after the turbo. Would it be better to get a short section made up so it is 3" right from the turbo or just try and clamp the 3" pipe onto the 2.5"

Cheers Rhett

Do the whole lot as the most restrictive part of the 4.2 GU is the dump pipe.