Paul ,
In THE most technical sense you need a C30E flywheel for a 5 bolt engine which came with a 160 tooth ring gear. Replacement ring gears are now 157 tooth. No problem. Yes the hi po version has the brinell test mark and "usually " an orange paint swipe along with the difference balance. The C5OE and C7ZE will interchange . If you are rebalancing the engine , a non hipo unit could be substituted. if you aren't , you would be best to use an original to get "close".
Randy