Hi,
I disagree with some of the above. I recommend a fmic for your car although top mount also fine but very small. No point fitting a v5 top mount as if your still running factory bonnet its inner tray is angled to suit angled v1/2 top mount. A FMIC with your TD05 16G will work very well.
Fueling wise walbro fuel pump, 440cc from v3/4 sti, and uprated fuel pressure regulator,
Fitting a 18g or 20g on your 17year old engine is a risk and also clutch will not hold up if standard or motor factor replacement at some stage in cars life.
Your ecu defo CAN be remapped with ESL.
Coil Packs may break down when extra load placed on them and are e350 set 4