4 Inch Exhaust improve MPG?

[mustangkcode]

Have a 04 Excursion with 6.0 I have installed cold air filter and a superchip in the performance mode. I have been told to install a 4 inch exhaust from the turbo back. I am happy with the current performance, I would change exhaust if helps further my mpg. Also someone a Meineke Muffler said do not do from turbo it will effect the turbo spooling, what ever that means??? Another shop said they do mostly from turbo back. Has anyone installed 4 inch exhaust and what was the results.
Thank you,
Mustangkcode

[07OUTLAW]

Upgrading the exhaust will increase engine efficiency, which, in theory, will increase fuel mileage. Real world- you MIGHT see a 1mpg increase. It is still a highly recommended mod though (especially when you start using a programer)

And go turbo back, the only thing it'll do to the turbo is let it exhale a little easier.

[Peppy]

i just put a 4" turbo back on and more power off the line faster turbo spooling and nice tone

[blizzardwarrior7]

A programmer will give you most power when you do the exhaust and the intake as well. A turbo back system is the most common, and the best IMO. The only difference is some people report slightly less low end power VS the 3.5" Downpipe....I however didnt..

[Patrick]

We sell them everyday. It will help with performance and economy, and it will help reduce your EGT's. Go turbo back for sure.

[6.0Sean]

I installed 4" turbo back to lower EGTs with the tuner, it spooled slower and lost low end torque at first (this was straight piped) I put a free flow muffler on it and it made a world of difference, spools fast lots torque, sounds great!