will mufflers gain much?
 

I had a friend give me some borla mufflers. I was thinking about putting them on my impala. Are just mufflers worth anything? Are the stock mufflers real restrictive?

Not at all, just good for sound.... But you might get a hp or 2 if you are lucky! :-)

well according to an article about the buick lacrosse suppers. They are rated at 300 not 303 like the SS and GXP. It said it was due to a quieter exhaust system. So your not gonna see alot . Nothing your gonna notice.

Going from stock to 3" all the back through some Super44s definitely made a difference.

Mufflers alone won't really do much for you, but it will make it sound alot nicer. So do it.