MSM axles
 

A pair of Mazdaspeed Miata half shafts. $300 obo. Email me at gibscreen_23 at yahoo dot com.

You should team up with the guy selling the mazdaspeed torsen for cheap. He has no axles, and you kinda need both to do the swap.

+1 teamwork

What are the differences between the Mazdaspeed and non Mazdaspeed? I thought that they would work in any Miata 1.8 diff.

I was under the impression that the MS had thicker axles.

Sorry OP, not trying to side track, just trying to help you get your stuff sold.

I just did this swap. The axles look the same, but may be different. I did not remove them from the CV joints, so I really can't say for sure. What is different are the CV joints. They are larger diameter where they fit into the diff, about 2mm larger if I recall. So yes, you need MSM axles (CV's anyway) to fit a MSM diff.

The CV would have nothing to do with axles fitting in the diff.

The axles do not fit into the diff, the CV does. The axles fit into the (inner) CV joint. I can't say if the axles are different, but the splined end of the CV joint is larger where it fits into the diff.

https://www.miataturbo.net/attachmen...ine=1330113798

That is a standard Miata inner CV joint & axle on the top, MSM on the bottom. On the CV joint, the seal area is the same, everything past there to the splined end is a larger diameter on the MSM CV joint. As I recall, 28mm vs 30mm.

Thanks for the clarification. When you said CV, I thought you were strictly refering to the joint itself. I thought that you meant the joint was more robust.

Correct me if I am wrong, but I considered the smooth and splined area to be axle shafts, and only the joint to be the CV, thus creating a shaft in multiple parts with the CV joining them.

I pretty much was doing that
It's bigger, so I would say yes, it probably is
The splined area in my pic is part of the CV joint as is the entire green area. The rubber boot covers part of the CV joint, I suppose one could argue both ways on if the boot is part of the CV joint. It will work without the boot, but not for very long. The axle is the round shaft between the inner and outer CV joints. Typically, its splined and snaps in the CV joint, under the rubber boots. Hope this makes sense.