So I just bought my 2013 GMC Sierra CC/SB 5.3 about a month ago. I like it but I'm sure you all know it's a little slow and the mpg can definitely be better. So I've been looking all over this site for a specific answer to my questions and I just can't find an exact answer to what I'm looking for. So I'm just going bolt on's. (For now until my warranty is gone). I think I've settled on TSP long tubes and most likely the SLP catback. I've read a lot about CAI's not being worth the money, is that true? I was gonna go Volant but I'd rather save $300 if I could. I already got a K&N drop in for free so I'm not sure what to do there. My biggest issue is cats. I want to stay legal for Texas and I'm not trying to wake the neighborhood when I leave for work in the morning. So what is the cheapest way to put cats in this set up? Buy hi-flow cats and have them welded into an off-road y-pipe? Will I need anything that isn't necessarily well known? Like O2 extensions? Heat shields? Are there any little misc. things that might pop up with this set up that I should know about before my truck is in pieces and I'm stranded? Thank you very much for any and all replies.....

 

If your wanting to leave cats and not void the warranty I would do a custom pcm tune, it will feel like a different truck.

 

Suggestions? Handheld or take it somewhere? If I took it somewhere I'd have to go back every time to get it removed right? So no headers? I'm definitely gonna go with a catback and from what I've read an aftermarket tube for my intake.

 

Save money on catback, just do muffler. Stock 5.3 has close to 3" piping, that enough flow in my book. Now headers&ypipe is good.

I think blackbear & autocal is good combo. that can switch back to stock tunes.

 

What kind of muffler do you recommend? I can't stand the drone so that is my first concern when buying any exhaust. Any suggestions on where to go for the blackbear/autocal?

 

Here is their website. They aint local, im still new to trucks/gm so dont know much about local tuner info.

Black Bear Performance :: Custom Tuning Solutions for 96 and newer GM Vehicles

I read many people happy with borla gmpp mufflers or magnaflow.