You guys are missing a key ingredient. The output shafts / stubs. All of the US 240sx and Z32 stuff uses 29 spline output shafts. Later S15 (and other beefier JDM models) as well as Q45 use 30 spline output shafts with a 1mm larger shaft diameter. Nissan basically put the larger R230 output shafts into the R200. It's the Q45 parts that get the notoriety because they have the 6x1 axle pattern to all out you to use Q45/Z32TT axles. There are plenty of aftermarket diffs that support the R200 30 spline arrangement. I actually had a KAZZ 1.5way that was 30 spline and had 3x2 output shafts.