Looking at the magnaflow catback but unsure if it's any good. Specs state that the tubing diameter is 4" seems kinda big to me not sure if it's necessary?

 

Whatever you want really.

Removing the stock muffler and flapper do more than the pipe size. Anything that is the same as the factory size is going to work. 4in isn't overkill but it's not a must do either, if you like the sound it'll be okay.

 

I thought I would have to have a diesel cat back. Thanks for cluing my slow *** in. I'd looked at their 5.3 but it was 3" and I've been pretty sure I wanted 4". I think It'll work. S E headers and ory with an dual 3 to 4 adapter and then the MF 4". That may be my ticket in the next couple mo. Thanks again!

 

Corsa sport hands down

 

He said it exactly right.

I like the forums because you get to hear everyone opinions but what are you looking for?
The 4" will make it sound little bit more deep and I like that that kit (assuming you talking about Magnaflow P/N 15318) is that it has the 2nd muffler/resonator. I hate drone!!

If you have a stock exhaust now, you'd be surprised how well the muffler and flapper delete sounds especially for $50ish at a muffler shop.

And lastly, on my old 2017 Sierra 5.3 I had a MBRP side exit P/N S5081409 and I loved it. I'd recommend MBRP again.

 

That's the magnaflow I was looking at. Do the Denali 6.2 come with a different exhaust system than say the SLT or SLE? Reason I ask is I looked under the truck yesterday and it seems like the pipes are 4" already?

 

5.3's are 3in and the 6.2's get 3.5 exhaust.

 

I can confirm that too.
I have a 2018 SLT and it has a 3.5"

 

I spent the buck on corsa and its sweet. just loud enough for my daily. cat back only. once you start adding headers or removing cats to make more power w a catback these trucks get stupid loud.

 

I have the flowmaster catback dual out the back and it sounds great. No drone and not over bearing but sounds good when you get on it. Nice deep sound.