Here is a link to our keyed crank hub solution:
This is a revised version of the prototype part successfully in use in my F80 M3. We have shipped a bunch all around the US and overseas, and there are a few distributors including ABR Houston and Lang Racing that have product in stock for local installs.
The install requires dropping the oil pan and pulling the timing components off of the car. It can be done in the car. The front of the crank is drilled through the crank seal opening using a drill and template, and the components are installed. Install by a qualified tech is necessary, as there are a bunch of factory tools needed to perform the job.