How is the flex plate balanced?

[nielsmobers]

Is it also possible that if new components (balancer and flex plate) are bought, that it is allready balanced, or is it allways nessesary to balance the engine. USA garages in my neighborhood tell different stories, one tells me that it has to be balanced, the other tells me that if the components are made for that car you don't have to balance?!? Now I'm confused... Is it a possibility to install the flex plate and then check if the car is balanced. Is it also possible to balance the engine by adding weights on the outside of the balancer like balancing a wheel.