Re: L/T X-pipe
as far as I know I haven heard of an X pipe set up for longtube headers. ANd really with the 3.8 I have heard more recommendations that true dual exhaust( you know not with and X or H pipe) is best for our cars. I have true dual and love the sound and performance. But really if you want that it sounds like you might have to have an exhaust shop build you one off. I don't think you have to worry about losing any torque due to back pressure as long as you don't go bigger than 2.5" pipes.
3.8L with Forged and Balanced Internals,65mm BBK Throttle Body, JBA Headers, Mild Cam, KN CAI, Port/Polished Heads, T5 with GT Clutch, Steeda Short Throw Shifter, 180rwhp/200rwtq, Foose Df-5 18", 14" Roush Alcon Front Brake Kit