C4 parts upgrade?

I need to know what stock parts I need to upgrade in my C4 trans.
It's in a 3200lb Mustang with a 400ci small block that makes 500hp on the motor and an aditional 250 with nitrous.

The C4 already has a JW transbrake, hardened input shaft, and heavy duty clutches. What other parts do I need to upgrade to make it last as long as possible?

Thanks.