Help out with some knowledge, I'm struggling - exhaust, tuner, CIA

Alright so the title says the gist. With my work schedule at the nights I never really get time during the day to seal out help or do much phone calling. I'm new to upgrades really and im looking to upgrade my exhaust, install a CIA, and possibly nab a tuner to help. I've pretty much decided on the S&B over vararam for the cleanliness and look. As for exhaust I'm lost, most of my looking in dealers I see stuff like the flow master American Thunder cat back for my 2012 express 5.7. But all my reading on here I just see muffler replacements? I don't want to break the bank so can I save on just muffler replacement or do I need the whole cat back set up since the oem muffler is roughly the size of a casket...now with these i know having a tuner will help me work on mpg and performance. Since I run interstate daily for work Id like to have an easy way to switch to a better mpg set up and then When I want some fast fun switch to a performance tune. I know there's alot of info out there for this but limited to using my phone for research at work it's tough. Is there a tuner I can get that's less than the diablos and bully dogs that'll work better just for my application since i don't plan on changing much else - cams headers etc...? Thanks for the help!

Welcome to the forum and great choice on CAI.
The muffler will be fine to replace as long as you aren't looking for doing a complete bolt on build or adding a supercharger as the stock exhaust flows pretty well.
Tuner, there isn't a tuner out there that will let you switch tunes on the fly like diesel trucks as these reflash the PCM rather than just piggy back on them. I would run the Diablo intune if you are looking to save a bit of coin and then get an custom tune from one of the tuners on the forum ie Hemifever or Jay Greene Racing. Good luck and keep up the modding.

Do the muffler swap as it reflects most of the improvements you'll see with a catback for a lot less money.

As far as a tuner, Etroze86 said it best. Get a DS tuner and a custom tune for best performance and fuel efficiency. You'll be happy you did.

What everyone else said...

I have the S&B and I went with that over the Vararam because of the winters (sleet and snow) we get on the East Coast... and I like the look of it... For exhaust, I'm partial to the MBRP gear... This is the 5th catback of theirs I've used... Love the sound... And yeah, a DiabloSport with custom tuning... With those three, there was a noticeable improvement over stock... I always run 91 octane too so that's the tune I went with from HemiFever...

Yep you can just swap a muffler in. Most cat backs use the same size exhaust tubing as stock so there's no real gain to buying a cat back. Unless of course you can sell the old system. (that's what I did) I went MBRP. Great sound and high quality, hands down the best exhaust I've owned. Plus their Canadian, so me being Canadian I'd rather give them my money than a US company lol.

I also chose the S&B. I don't know if I found a power increase..but it sounds meaner.

You won't save enough mpg with the tuner to ever have it pay for itself, so don't get your hopes up. It might get you .5-1 mpg better, but you'll get more smiles per gallon! Lol

Good choice on the S&B had mine almost three years now.
You can swap the muffler for the desired effect cheap and easy. There is no reason to replace all that OEM piping just put in a new muffler--although if you go to a shop they will probably use aluminized steel pipe instead of the factory stainless.
It sound like you don't have a lot of off time, so that may be the best course for you to follow, but Mufflex makes a DIY kit that is all stainless with three sizes (14", 18" and I think 22") of Magnaflow muffler that is a direct bolt-on in place of the original ship's anchor sized muffler. Moe's Performance (link ---->) carries the Mufflex and some straight mufflers too. If nothing else, and you can find time to call, talk to Matt for some straight talk on mods and tuning too.

Awesome thanks for all the advice! So now, here's my next question, how in the hell to choose a muffler? I liked the american Thunder sound I guess, I like real deep and mean ass sounding with less crackle. I can't tell jack nothing from YouTube videos on my phone...and this might sound like a dumb question but do they come with a tubing to make up for the length difference in the swap for oem since that oem is roughly the size of an Olympic pool?

love my 14'' Boeschbuilt Magnaflow kit... highly recommend!

Yes each kit has the length needed already welded on so it really is a quick bolt and go type mod.

No matter which muffler you go with, it will be considerably smaller than stock, which will increase not just the sound level,but chances of getting droning on the highway and when MDS (4cyl. mode) is on.

If you buy a DS tuner from Hemifever (a very reputable custom tuner- check out his website) he includes a free custom tune. You can't beat that.