Z4 35is Propshaft CV Broken

[JohnDG35is]

Hello

I have a 2010 Z4 35is. I’ve installed hybrid turbos and various supporting mods so power is around 550hp to 600hp. I also have H&R sway bars and upgraded rear subframe, diff and wishbone bushes to powerflex.

I have broken the small cv joint on the propshaft just before the differential. The CV joint cannot withstand the torque level if I launch the car. So I need a solution for my power level.

The M cars have a much stronger CV joint(34 spline 108 OD). I can buy the CV joint(Number 17 in CV.Pic) but the Propshaft and the diff input shaft will have to be modified. My diff has a 34 spline input shaft with a sunk nut and no thread to secure an input flange to the diff. So I will have to open the diff and install a new input shaft with threaded area for the nut. I need to know the Z4 35is diff size(188mm or 210mm) to order the new input shaft?

Or possibly, machine thread on the outside of the new input and use the sunk to secure it to the diff and then just bolt on the propshaft?

Is it possible to install another Diff, propshaft and output shafts from an E90 M3 or E46 M3. Not sure if this is possible? Has anyone done this before?

What is the best solution? Can anyone confirm the diff case size for the E89 35is? Think its 188mm but not sure?

Regards,

John.