MSM used shot-peened gears in the tranny IIRC. Unsure about the diff.

 

Pretty sure you're right- I sourced my Fuji 3.90 LSD from an '05 non-MSM. Combined with the '04 MSM motor and six speed it should give the car good legs.

Speaking of diffs; I have the open '99 rear that came out of my car if the OP needs it. (Or anybody else.)

 

Thanks, I think it's pretty cool how many parts are cross chassies with the miata. Joined here to try and sponge as much info as possible.

 

OK crew- OP might be interested in my stock 1.8 open diff. 120k miles and in good working order. (Whole center chunk)

What's a fair price for this noob? I truly have no clue.