Rear Subframe Bushings

Although I plan to stick with OEM M Roadster suspension bushings and bits in most places, based upon input from those much wiser than I in the ways of the Z3 platform, the use of polyurethane bushings to mount the rear subframe can possibly extend subframe spot weld longevity. I was initially going to go with the Ireland Engineering poly rear subframe bushings (RSBs), but they were back ordered and I have heard rumors of quality issues, so I ended up with Powerflex parts.  I installed the purple "Street" durometer, which is rated at 80A, approximately 30% stiffer than a rubber bushing.  The Powerflex black race bushing durometer is 95A, approximately 80% stiffer than a rubber bushing.

Powerflex Street durometer RSB and an OEM RSB:

Powerflex and OEM RSB.png

Powerflex Street durometer RSB and an OEM RSB:

Powerflex and OEM RSB 2.png

Powerflex rear subframe bushing installed:

My OEM bushings were fine, and I haven't noticed much of a difference after the Powerflex installation, but it will be one less thing to do when I eventually tackle reinforcing the rear subframe assembly with the Randy Forbes kit I have on the shelf.