These are photos of the bump stops that were taken off my car. These bump stops came with the BMW performance shock kit that I had installed some time ago.
Now, the kit I'm talking about is the "Version 1" kit; the kit available today is different and includes springs.
Here are the bump stops together with the ZSP bump stops, so you can compare. From left to right, there's ZSP front, Performance front, ZSP rear, Performance rear.
The performance bump stops are longer than the ZSP ones. This I think is strong evidence that the ver.1 kit was intended to be used with the original springs. BMW is using these bump stops to add a little spring rate to the ZSP springs.
31 33 6 767 333-01 ZSP Front bump stop 2.75", weighs 58 g
31 33 8 036 012-01 Perf (Ver.1) front bump stop 2.94", weighs 63 g
33 53 6 767 335-01 ZSP Rear bump stop 2.88", weighs 51 g
33 53 8 036 000-02 Perf (Ver.1) rear bump stop 3.06", weighs 75 g
Again, the specs on the bump stop I'm using now:
33 53 6 761 903 E85 Z4 2.5i rear bump stop 2.50", weighs 35 g
(The way to order the E85 stop is actually p/n 33 53 6 770 350, which includes bump stop and protection tube)
Here is another shot from an angle.
