Good pads and good fluid will = almost identical stopping to any brake upgrade. Repeated stops heavy stops will benefit from a brake upgrade.
My two cents is to install all your gear, turbo, nistune etc. Drive and enjoy.
When/if the rotors need attention then machine them if they have enough meat, replace the pads (if needed) to something that is consistent with the cars use and replace the fluid if it is buggered.
I recently replaced the front and rears calipers and rotors for R34 GT-t + DBA4000 (they are not quite direct fit) and the initial impression is that braking feels pretty similar barring getting rid of the slight pulsing from the warped/glazed front rotors.