VS cars come standard with lap belts. The best examples of shoulder harnesses I have seen are aftermarket or home fabrications employing correct, structurally sound roll bars with a cross bar of the proper height. It is very important that the angle of the harness from the horizontal is shallow, since when stressed, such as in an accident, the downward forces generated (ie. pushing the shoulders down toward the seat bottom) must be minimized to prevent spinal compression. What ever you decide to do, be sure to do your homework.