If by "regulating rod" you mean the tension strut (the arm that goes forward from the bottom of the strut), then you have three choices:
1) buy the complete E9x M3 tension struts (31102283575, 31102283576), which has the upgraded bushing which is stiffer. (
see here)
2) just buy the E9x M3 bushings for the tension struts, and press in with a hydraulic press (2 needed: 31102283579)
3) Or as I did, order up a solid spherical bearing,
such as the one by AKG Motorsport, to replace the bushing (like #2).
#1 is easiest, #2 and #3 are easy if you have a way to press the bushings out and in.
Good luck!
Filippo
