I had an OFNA 9.5 pro with a PBS rear at one point. For club racing, I would just add high torque servos for both steering and brakes.

Any other upgrades would be a waist of money for this model. It is your driving skills that will make the biggest difference.

Shocks - 35 front/30 rear.
Diffs - 5000 front / 7000 center / 3000 rear

Get good tires - Crimefighters are safe good choice.

As to selling it....you will take a huge loss from the $400 you have in it.