Rear-most frame rails are welded in place, and those flimsy little metal plates that BMW thought sufficient to hold the head-stock steady are trashed and replaced with some good stout tubing:

resulting geometry:

"I assembled the front end and wheels. The steering head angle is 26.5 degrees with the bike sitting on the bare wheels and the forks slid up in the triple trees 1 inch. With tires it should be about the same or slightly less (26 deg). The trail figures out to 3.96" at 27 deg and 3.69 inches at 26 deg so we are right in the ball park." – Randy Illg