What works best for maximum gains?

Are you referring to a 3" single vs a 2.5" dual? The dual will allow more air flow.

I had a 3" dual but it was painfully loud so I swiched back to a dual 2.5" and I am not sure if I lost power but I dont even care the car is so much nicer to drive now.

I see dual 2.5" it is!

Crazy, i'd imagine not much could out perform a 3" single setup

A 3" dual
A 3" single would work great on a single turbo setup. If there's 1 turbo per bank though, then theoretically a 2.5" dual should permit more air flow then just one 3" pipe. I'm not a tuner but to me that makes sense.

2.5" TD will be just fine up to 500whp or so.

Or 625whp

Even going to 2.75 asks a big commitment- the noise is a lot more of an issue by a long shot. I went with 3" down pipes too... Which don't help.

I'm really, really hovering on switching those back out for my 2.5s... It really just makes the car so much more relaxing to drive yet with most if not all (at my level) of the power available.

If I did the heads and got bigger turbos- okay- now the 3s make sense... But not at this point.

Two 2.5" pipes will flow about 36% more than a single 3" pipe, given that we are referring to nominal OD with a .063" wall thickness and ignoring skin friction losses.

The bigger the pipes the faster the spool. And more power. Turbos needs as much airflow as possible

I got dual 3"s

It's not that
Our, the turbo cuts a lot of the sound out with the right free flowing mufflers. My car is quieter than half of the na vq's

^what exhaust homie, I can only find 2.5 dual, hell all the hks' i see are smaller than that. I like the Ark grip but it is only 2.5

Had my car for the past 3 days which is also 3" downpipes and the Greddy Ti-C dual. It was extremely loud and droned like crazy at first. But, I just installed the silencers tonight that came with the exhaust and those made a tremendous difference, probably about 50% quieter. My previous HKS dual(2.25") was louder then what I have now.

Install the silencers and you'll see the difference

Getting the pricing for the AAM Competition 3 in. True Dual Exhaust (Titanium). Time to let the twins breathe!

With open dumps you should be fine with 2.5