You don't need to drill anything. Put helicoils in the caliper, much easier and not destructive. Note the bolts will be different (1.5mm pitch on the Brembo calipers, 1.25mm pitch on the Sumitomo calipers).
the R33 brakes should be fine though, the GTS-t is lighter than the GT-R. You'll probably get better performance from higher temp pads and ducting. The Brembos do look better though.
Can't comment on the combo, but I think the bias will be off slightly (bigger calipers up front). In saying that, it should work fine (I did a track day with 34 front Brembo and standard 32 rears).