Wombat, Everyone has the same problem with the bumper brackets. You have two choices. Either do as Wolfgang indicated (that's the common solution). Or build your own bumper brackets. You may want to check my profile page and look for driving light mounts. This design could be modified to be used for the bumper mount with heavier angle
I also built a sway bar for my Spyder that bolts to the VW front beam. It will work on the Speedster without modification. Dannyp built one of similar design but easier to build and accomplishes the same thing.