Convert early 915 to Omega spring setup?
 

Anybody do this? Looks like I would need the shaft and the arm, spring, bracket and cable. Any catches?

You need to cut a notch out of the rib where the serial number is.
Other than that, it's a pretty easy swap, if you have all the parts.

The cross shaft in the pedal cluster is different for the later cars that came with the helper setup, as the lever arm is longer for more clucth actuation, but it's not absolutely necessary.

You'll also need the brackets that bolt to the side cover, and 4 longer studs on which to mount them.

Gearbox has to come out to do this, of course.