4" exhaust

[maverick_935]

looking at a 4" MBRP exhaust that bolts to the downpipe. Is this good enough for EGT readings to lower or do i have to put the turbo downpipe on?

[More Power]

No doubt, a complete system that includes a free-flowing and larger diameter downpipe will help to produce an EGT reduction. The real question is how much of a difference will a downpipe make in EGT all by itself and at what cost. If you're building a competitive race truck, then sure, it's part of the deal. If you're a typical Duramax owner, I'd put the money into something else.... The exhaust system upgrade, otherwise, is a good idea though. ;)

Jim