Does anyone know if an aftermarket big brake kit off a 33 GTS should fit a 32 GTR ok ?
Untrue. R32GTR brakes are 296mmx32mm and R33GTST brakes are 296x30mm.R33 Gts-t uses R32 Gtr front brakes so it should be a straight swop. I have aftermarket R32 Gtr discs on a Gts-t and they were a bit tight with new pads, it was sorted by removing the anti squeak shims. The disc make is DBA.
Your kit is doing the same in reverse so should be OK.