I have not answered in this becuase I think that this could be a waste of money.
I will be the first to agree that an aluminum pionion bearing is much superior in strength.
I am also amongst those who will tell you that the weak factory non-nodular thrid member case is not a good choice for any type of racing. It will not hold up long with even a mild engine.
A stock 8.8 Mustang rear would be much stronger than a stock 9 incher.
Ford 9 inch rear ends are not inherently strong. They have the capability of being made to be strong with aftermarket parts and welding.
A factory rear end that is inherently strong is the old Dana 60. That is a little heavier but will handle much strength as it comes form the factory. Even the Mopar factory axles are fairly strong, as compared to the best from factory of anyone.
Ed