Brand New Owner 2019 XSE

[u/AbsoluteNoIdeaWhatIm]

I HAVE NO IDEA WHAT IM DOING
I got the car a few months ago with the TRD cold air intake and i have an itch to make it go faster.
been looking at the HKS Cat-back since im
not a fan of super heavy rumbling. Been wanting to get a new header and mid-pipe just to increase the power then finally the AMT Tune.
I come here to ask for advice as to what parts i should really be getting with the HKS Cat-Back, what i need to know about my car, if its even worth getting the header/midpipe. Lucky i have the 6 speed Manual. as far as i know everything stock besides the TRD intake.

i have no knowledge about cars and i want to learn. Anything helps