M3 rear brake retrofit

[GeorgeH]

Bare with me here, this makes sense in my head. I wasn't sure if this is a suspension or a brake question, but I'm starting here. lol

On my wagon, Eileen, I still have the 325 trailing arms but have swapped to 330 brakes. The downside to this is I do not have a functional parking brake at the moment. My goal in this project is 2 fold:

1. I want to have a parking brake.
2. I want to swap everything to M3 brakes (front and rear, booster, ABS, etc) as well as the complete front suspension.

The reason for keeping the non-m diff is that I have a 4.44 out of an X3 in the car with a Wavetrac, to get something comparable in the 210 diff would be a $3-4000k minimum adventure. I would rather spend that money on a BBK for the car.

SO my question is can I put M3 trailing arms on the car and keep the 325 subframe and diff. I would use 330 cv shafts (and obviously flanges on the diff).

This is why I think it is possible:

1. The upper and lower control arms are the same for both cars.
2. The 330 and M3 CV shafts use the same axle nut and it appears the splines are the same od.
3. The 330 and M3 have the same rear track width.

You would think I would know the answer to this but I do not and searching is surprisingly difficult consider all the threads about putting M3 brakes on these cars (usually complete subframes). I have all of these parts but they are assembled in various systems and cars and it would require disassembly. Does anyone know?

Thanks, George

[RUS_ZHP]

I wish I could help with this, but have zero experience with it George. The only nerds like you will have the answer-))
Good luck with this project!

Sent from my SM-G960U using Tapatalk

[squashman702]

Seems like a lot of work for what's still a single piston caliper and only a slightly larger rotor. Why not just swap to 330i trailing arms? Subframes are the same, so you'd only be sourcing axles and trailing arms, and you'd regain Ebrake functionality.