I'd like to install a shift light. There are several candidates. They all say they won't work with the high voltage from the CD box, but will work with other wire/signal, probably a wire going to the tach? Has anyone done this? For a 70 914-6, how is it wired? Can anyone recommend a shift light that has worked for them?

try the paddock part of this forum for that. i think i've seen a shift light on here once. kindof a civic type thing to do as i've seen.

I put a shift light on my car. The light came with the Autometer Monster tach which fits perfectly in the stock tach hole.
drilled a hole on the left side of the binacle for the wire. and glued the light to the top of the dash with marine adhesive. The autometer tach drives the light.