Go for 1.5...
Ur brakes and suspension dont need to be uprated, just get good quality braking pads...
Gearbox will remain same, Only engine assembly will be changed... U will have to change engine mounts as well...
Exhaust will be modified to fit the reverse placement of headers for 1nzfe...
Try to source a clean engine... Mine has done over 30K and still goin string mashAllah with excellent average, mines manual though a bit on the expensive side of swaps...
Cheers...