Welcome to the site Nick.
All of those parts you have mentioned will work wonders with the s12.
Fitting bcpr7es plugs spaced to 0.9mm, Boost set at 12psi with a front mount intercooler of your choice along with a filter and freeer flowing exhaust system will completely change the cars performance for pennies. Try removing the centre silencer at the same time when you do the rear silencer.
Where abouts in the country are you?
Richardk has fitted safc to his s12 sucsessfully using 370cc s13 injectors
Give the beauty a damn good service before you tune her up.