Shoulder belts - roll bar?

I am going with a 5-point harness, but this car will see more street than race, so I also want a standard 3-point shoulder/lap belt. At this point I'm looking at Seatbeltsplus, something like this:
3 Pt Dual Sensitive Retractable Seat Belt Chrome Lift Latch, Black
I think it will require a welded tab for the shoulder pivot, but other than that should be bolt-in.