I've a 2000 Sierra Ext. cab short box with a 5.3L & stock exhaust. My first step is to modify the exhaust with a catback system. I'm interested upping my HP but not in breaking windows. I'll probably use a 3" pipe but do I use a gibson, flow tech, flowmaster or a soup can?

 

My personal preferance is a flowmaster, there on everything I own, from my plow truck, wich is a toyota, to my 6 cylnder gmc, I like them, I have a 40 serries with dual 3" pipes on my 87 f-150, without cats, and its a nice low mellow sound, no bark to speak of, and wont break windows, im sure yourse will sound diffrent but with 3" pipe, there isnt alot of snap, or bark to it, but any smaller, thats a diffrent story, my buddys got a 98 k1500, with "true" duals, 40 serries ORIGINALS, and small high flow cats, 2.5" pipe, and that snaps and barks from 3,000 up. its all in what you want I suppose, I favor Flowmasters, but thats a personal preferance. and they make many mufflers depending on what you want to hear, from loud, inside and out, to quiet, inside and out.

 

I prefer the Magna Flow, Had on both my 99 asnd 04's love the sound and the little extra boost in performance, which ever way you go spend the extra and get the stainless steel one.