Does a high flow muffler really help?

[Farmer_Chevy]

I bought an 05 Z71 with the all aluminum 5.3, I read that on the newer 6.0s that your really dont gain much with an exhaust. Is this true with the 5.3s as well?

[Dave12]

I don't think exhaust alone makes a whole lot of difference. Once you start adding the performance mods to the engine then you need to upgrade your exhaust. Doing exhaust without the other stuff just usually looks and sounds cool without really adding any noticeable performance improvements.

That's my opinion anyway others may say different.

Dave