The E500 should be the same as other gearboxes of the time.
If left in Drive, the car will pull anyway in 2nd gear, no matter whether you are in Sport or Economy mode.
If you move the gear lever to the "2" position while stationary, the gearbox will go into 1st. Leave it in "2", and it will upshift automatically from first to second, but then not change into 3rd until you manually change it.
Also, while stationary, if you move the gear lever into position "2" and then back in Drive, you will pull away in first. It will then just upshift as normal.
Also, as pupsi mentions, if you give it the beans off the mark, the gearbox will kick down.
The other 2 ways I've mentioned, means it should be quicker off the mark, as the gearbox won't take time to change down.
HTH
Also, does Berg Werks still exist? And if so, do they still upgrade W124s?
I know
Renntech also used to do a first gear start module, too.
I think I read somewhere, MBClub member
talbir had/has a 1st gear start module on his 500E and his old E500 (now owned by
jaymanek).
Darren