My 5K
Springs/shocks: Eibach Prokit springs and KONI FSD shocks.
kit is about 1200AUD delivered from america, NAmotorsports or another forum sponsor will help you out.
rear sway: whiteline RSB $250 or less
whiteline antilift kit: $220 adds castor and helps reduce wheel hop.
downpipe: $1000 Take your pick of brands, but something that mates to the stock cat back is the way to go. better/quicker spool and more turbo noise
intake $350 take your pick again! twin take is nice but $$$ dont bother with a carbonio.
stage 2 ECU flash $1000 aud (GIAC/REVO/Bluefin)
RDA front slotted rotors and new pads $500 IMO the stock lines are fine, but a flush, or at least taking out the fluid close to the actual brakes, is a must
Torque arm insert $100
with the last $500 you can pay for someone to install it all, or if your keen for DIY get a set of KU36 rubber, the 235/45/17's fit with the fender screw mod and will stick like shit to a blanket. bewarned you'll only get 15k tops from the rubber, if treated well.
Next would be lightweight rims, and then a upgraded fuel pump.
Most of the coilover suspension in australia isn't ADR approved, and the ones that are (TIEN, KW v3's) arent cheap! hence the springs in my package.
the above is the setup on my car and I'm very happy with it, its balanced and has enough getup without being overly scary. has a very nice ride for a daily as well, but will handle track duties when required.