I currently have a 2008 gt 4.6L, with a k and n intake and a Borla Exhaust. I am looking to get even more horsepower and I am considering either headers, a chip, or both. What will have the most impact in torque off the line, and will either help gas mpg? I am pretty sure I will have to get shortys if I get headers becasue I've heard long ones dont increase speed off the line as much and the whole exhaust manifold has to be replaced.

I could use some help.
Thanks

 

First, these cars don't have chips, the use a tuner. Two of the main ones are SCT and Diablo. I have the diablo and it does have a tune for the K&N. Companies can email you tunes for your tuner. Keep in mind that the only company that I know of that can email you tunes for the diablo is Bamachips. Bama chips, Brenspeed, VMP, and tricktuners...I am sure I am missing a few, can email you tunes for the SCT. If you buy the tuner from Brenspeed or Bamachips they will give you three free tunes. The regular price of the tunes are 50-$75 each. Second, don't waste your money on shortys. I don't have first hand expereince, but long tubes do increase hp, but I would not get them before I get gears. Most people recommend 3.73s for auto and 4.10s for manual. With a new tune and gears your overall gas mileage probabally won't increase but probablly won't decrease either.

 

Underdrive Pulleys free up some HP if you dont have them installed already. I have 4.10's in my auto and love it.
I like the Borla sound it could be my next mod.

07 Black GT
Auto
JLT with SCT Custom87 Tune
Steeda UDP's
FRRP 4.10

 

Some long tubes and a custom tune will open that thing up, andyou can specify what sort of tune you want. 1 for hauling, and 1 for Grannie Mode/MPGs.