Z4 SMG v M3 SMG - what's the difference?

[Sortie 10]

What are the technical differences between the two SMG systems? I know that the M3 version is multi-mode and the Z4 system is not.
I have been told that the Z4 has a torque converter fitted (and so is akin to a tiptronic style auto box) - is this correct? Also that Z4 is a previous generation.
Would welcome any advice regarding the mechanical and driving differences, and also a link to any on-line Z4 handbooks/manuals.

(A pal has just bought an M3 SMG, and I am considering a secondhand Z4 SMG)

[toppstuff]

The Z4 SMG is definately NOT a torque convertor jobbie.

I think it is essentially the same set up as the M3, but with simpler software and less ability to alter the mapping and the "aggression" of the shifting, like you can with the M3.

With the M3 you have launch control, and the option of several different settings for the gearchange from "soft and lazy" to "fast and harsh and did I break something".

Z4 has few options, and is set a default medium level I believe.

[Zod]

Toppstuff is correct. The other difference is that instead of the sensible, logical up on the right, down on the left paddles of the M3 SMG, the Z4 (and all other non-M cars) have thumb paddles that work the same way on both sides, i.e. push to change down, pull to change up (or the other way round).