I done a short shift conversion on my E30. I used the Z3 2.8 Lever. The result.....brilliant!
At the same time I had the propshaft out on the M5 and it was up on axle stands. I decided to get under there and do a bit of measuring.
It turns out that the distance between the Pivot ball and selector rod is exactly the same as that of a standard E30.
The shape of the lever is very very similar to that of an E30.
The Pivot ball size is also exactly the same.
Therefore the Z3 1.9 or the 2.8 gear lever will go straight in.
The only thing you may have to do is slightly bend the selector rod upwards, you have to do this on an E30. Its only a small amount of bending and not enough to cause any weakening of the selector rod.
You can also use the Z4 Lever, its shorter in height and even shorter but will be quite Notchy.
There you go......some research done in the name of the E34 M5!
I doubt I shall be getting the UUC now as I cant see how it will be any better. Might just get the DSSR though.