5.2 Magnum is basically internally balanced, so it takes neutral converter and neutral flex plate. No problem.
5.9 Magnum is external balanced and it's different than LA external balance.
SFI rating meets race sanctioning rules for safety.
Any street car can just run one made from a template or fabbed from something else.
The stock 360/5.9 Magnum flex plate works on mild builds for the street, but a stronger one is a good idea when pushing around 400 HP or more.
Any 360/5.9 Magnum that has been balanced internally, such as aftermarket cranks, no longer needs Magnum specific balance parts.
If I missed anything, feel free to comment.