I have an 07 GP GXP 5.3 v8 engine.. I have a issue with a leak at some point in the exhaust system and since I will likely need a new pipe someone suggested I'd do well to increase the size of all the piping front to rear with larger diameter pipes which would increase horse power performance.. Is this a sound suggestion? I would use stainless steel pipes for this. The muffler is still in fine condition but if I do change the pipes to a larger diameter can I use the muffler or would that need to be changed to match the new pipes? Does anyone know how much larger can I go with the pipes and can anyone suggest what size would be appropriate for this engine? If the muffler has to be replaced does anyone have any recommendations for which one would go nicely in this situation? How much added performance might I expect having made the exhaust improvement as I have explained. Thank you

Negligible....you certainly will not "feel" it....before and after stats on a dyno, would show some improvement, but like I said, you wouldn't "feel" it....and isn't that what it'* all about?

It'* like guys who install glasspacks.......it sounds like it has more power, but it doesn't....

Not worth the time and expense....

Like Tech II said, not worth the time and expense on a PCM controlled engine, on the pre-computer V-8'* you could light their fire with some intake and exhaust work.

2004 Bonne SLE
1971 Chevelle SS

Thanks to the both of you for your responses.