I'm going to bring this back from the dead. I have a similar dilemma, I don't really want the added weight of a half cage and I'm only going to be driving around on the street. I want to use the the strut tower bar to mount the should harness straps since it has the proper angle for safety, however I'm not sure which rear bar would be my best / safest bet. I emailed PDK and they no longer make their bars. My old MSA bar seemed solid but since it's adjustable it might make it weaker? Top end makes a triangulated bar (below) but it has an extra piece of medal welded where the straps would go causing the straps to not be centered.
Anyone have any suggestions for a rear bar that would work? Normally I could care less about adding a racing harness to cruise around town but the original shoulder belts are 40 years old and appear to have a decent amount of sun damage.