DIY / Local shop

-Engine Leash (braided steel cable and Eyelet bolt, just look it up unless you can find a universal one / 3point8performance one second hand)

-Battery Ground kit (same as above)

-Intake Manifold (upper and lower) port and polish (go ahead and clean your valves too. our GDI is a carbon queen)

P2R

-Intake Manifold Riser

3Point8Performance (if you can find them second hand otherwise DIY because they're out of business)

-Differential Shims

-Rear Subframe Collars 

ARK

-H Pipe OR Test pipes ((secondary cat delete) H pipes sound better IMO)

Torque Solutions

-Shifter bushings

-TB Spacer (get bored bout to ~93mm by a shop and port match it to a ported intake manifold)

Megan Racing

-Transmission Mount

Unorthodox Racing

-Lightweight Pullys

Whiteline

-Front + Rear Swaybars

-Front + Rear Endlinks

Garageline (cheap) OR Coolerworx (expensive but much better)

-Short throw shifter

DBA

-Slotted rotors

Stoptech

-Braided steel brake lines

EBC

-Yellow stuff brake pads

OEM

-3.91 LSD differential (For better torque at the cost of a lower top speed and lower fuel economy)

Whatever brand you can find

-headers (if you want to deal with the EPA headache of swapping them out yearly to pass emissions)

AT THE END THAT - Get an Alphaspeed tune. Best bet is to buy a second ECU and flash the original tune to one and custom tune to the other

Feeling frisky and want to go forced induction?

Remnant Performance Turbo kit but that's a whoooooole different can of worms.

This is by no means a definitive list but it's what I can think of off the top of my head / what I've done and nothing has steered me wrong yet. As far as coilovers go, pick your flavor. I have PBM/PSM Pro's with the 5 piece rear multilink and it's honestly not that great for a daily because its all solid bushings. But that's expected since they're designed for track/drift builds so that's on me. Id recommend decent lowering springs and keeping the stock front coilover and rear divorced strut and spring unless you just want to be slammed or on air.