xr8eater, Aus R31 with A/C (twin core); 660mm wide, ~510mm high overall (core is 400mm high), 34mm thick core, but the top mounts are different. R32 RB20DET & RB26DETT (from R32 engine manual) 646 wide, core 380mm high, 25mm thick. So there is a great improvement if it will fit.
Carlos