Stock turbo is useless above 17.5psi(blows hot air), but it can handle up to 22-23psi(don't recommend it though).
You don't need to worry about the injectors unless your doing a full rebuild. The injectors are inside the block and you'll reach the max of the internals before you need new injectors. (It's very different to the convential setup)
If your car is tuned properly, you don't need the upgraded fuel pump on a stock setup. That said, as soon as you slap a bigger turbo or want to push for bigger power you will need this mod. It won't hurt if you run the bigger pump in a stock engine/turbo.
My stock clutch let go @ 190kw atw. Put in a lighened flywheel and a stage 3 Spec which did the job.
You won't need a thicker head gasket unless your planning to play with the internals of the engine.
What's your plans?
CorkSport FMIC with Cold Air Induction, , Cork Sport Cat Back, CPE Standback with PNP, TurboSmart BOV, Custom Highflow Cat with CorkSports Downpipe,Pauter Rods, CP Pistons,ARP Head Studs, BIGGER TURBO COMING, Pre-ordered a Stage 3 CPE Engine.