RE: Headers
If you have the 5.7 the headers will be well worth the money. I just installed my JBA shorty headers and while in the process, looked over the stock exhaust manifolds and they are rather restrictive. I have the 6speed which comes factory with the free flowing exhaust system and I still noticed a difference. I prefer the shorty headers because they are 50 state legal but unfortunately don't have the "sound effect" the long tubes provide. So to sum up, if you re gonna spend money on a complete system I would certainly replace the stock manifolds. Best of luck.