u need ecu, or get urs remapped, injectors, fuel pump, its better to buy a half cut as it has everything, but if you dont want to do that, you can get a rb25det block and fit your NA head on, or buy the two seperately, either way you will need bigger injectors. It is better to have proper DET parts, as the compression is lower and you will have the oil squirters in the block.
Another way that you can do it is turbo you NA motor, it is possible, but the max boost you can run is 6psi and the motor is very torque as boost comes in at 2500rpm.
If you have any other questions let me know, i am able to tell you the parts you may need depending on which way you want to go.
cheers