Rebuild the internals of the upstairs guest bathroom toilet. Replace the tank bolts for good measure. Replace the failed toilet shutoff valve. Pressure was at 80 PSI, I explained that the PRV is on its way out and left an estimate to replace it. A failing PRV will gradually increase the pressure on the home side until it matches the higher street pressure. This is typically higher than what fixtures like faucets and toilet fill valves are rated for (>85PSI), putting unnecessary strain on both pipes and fixtures.