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Yeah I'm thinking that'll be where I end up, just swap out the centres. Only problem I'm really running into is sourcing one for my specific model. RHDJapan lists the "RB25DE non-viscous model" and the "RB25DET MT" models as using the same centre. Which I would take to mean that, if they use the same model, then they have the same axle hubs, which we've been over pretty thoroughly as not being the case. Could just be more to do with the ratios instead of the actually parts but it doesn't clearly state either way, so will have to shoot them an email to confirm.

Nengun also has the KAAZ model which differentiates the models a bit more clearly (25GT and R33 GTS use the same centres, like we were saying earlier) and is about the same price as the Nismo (RHD actually works the Nismo out a bit cheaper with shipping). Probs be more inclined to the Nismo side of things with that being the case but if anybody's had experience with either or better yet both I'd love to hear about it.

Keep in mind the following permutations of the possible differences between stub axles across the various diffs.

The centre can be open, viscous LSD or helical LSD.

The stub axles can be 3x2 or 5 bolt (we'll ignore the GTR 6 bolters).

The splines may be different (diameter & count)

The lengths of the stub axles (and therefore how far in the splines go) can be different.

You can have any of a whole bunch of those factors in play at the same time.

Example.  Silvia VLSD.  That's going to have 3x2 stubs, but the stubs will probably be the same diameter, same spline count and same lengths as the 5 bolt stubs on an R32-4 VLSD.  That's because it's the same centre.  It is important to note that the VLSD is an odd looking thing inside, and this means that you end up with two stubs with different lengths that actually won't work in other centres.

Example 2. S15 helical vs R34 helical.  I'm pretty sure these are the same centre.  So the 5 bolt R34 stubs should go into the S15 centre and vice versa.  But you can't use these stubs in a normal mechanical LSD (say a KAAZ).  At least I don't think you can.

When you buy a Nismo diff, I'm pretty sure that you get stub axles to suit with it.  This because of the odd length stub axle situation from the VLSDs.  I think that the open centres use different length stubs to the viscous diffs, which is why they list different Nismo GT centres for open NA diffs and for turbo diffs.

Be aware that there is a hell of a lot of noise in what I said above, because whilst most of it is right, there could be some things I said that are not right, simply because I can't keep it all straight in my head, and have never known it all properly anyway!

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