Does exhaust help performance or just sound?

[emann_01]

How can factory cats with all this "go green shit" and emissions be high flow? ill believe it when i see something about these.. ill take you up on that one..

multiple trustworthy and knowledgeable people on this forum agree and have posted so (including vendors)...due to new technology, "going green shit" doesn't necessary inhibit performance

 

[blueflamed03]

And also for an 04 Yukon

for the money, LPP's...

 

[yukon2004]

for the money, LPP's...

Cool, thanks!

 

[ezdaar]

I gained alot of top end from doing a muffler back, but lost power from 1800 down..