What should I get next on my '13 5.0? I have K&N CAI, Roush Axleback exhaust.. thinking of either going with kooks 1 3/4 headers and x pipe to finish the exhaust, or 3.55 gears and Bama tune..

 

You need a tune before going to long tube headers.

 

Tuner has been ordered already, but thanks

 

What's the difference between lt w/cats and w/o?

 

I imagine you'll feel more with taller gears, such as a 3.73 or 4.10, instead of the headers.

 

LOL one comes with cats and the other doesn't.
Not on these cars. Please refrain from giving out bad advice unless you actually know or own one of these cars. Someone might take you seriously and make a poor choice.

 

I know that, I mean is there hp gains with or without or does it matter?

 

Think it would be wise for me to stick with 3.55's since this is my daily driver.. 50 miles to work and back

 

is yours an auto or stick. if its a stick you prolly have 3.73 or 3.31. auto I think its 3.15.

 

If he has 3.55's then it's the MT-82. Those come with 3.31's, 3.55's, or 3.73's.
Autos come with 3.15's only.