"What else is there that wears out that could majorly affect the handling of the car?"
Its your diff
I love the Pro 4
My car would push getting into the corner then the rear end would want to step out on me coming out of the corner (FTTC3 never did that). I tried everything to get the car way I wanted it, I put in a one-way, messed with droop, sway bars, springs, shock oil, rollcenters, camber link lenght, put associated parts in the diff, and even tried different bodies.
All the changes I made were helping, but the car still wasn't where I wanted it ...setup wise. Then I came to find out my rear diff was too tight. A buddy of mine took my diff apart and found that the diff grear was causing the center bearing to bind (the bearing was fine). He put a diff together for me before my main the car worked just way I wanted it to. The car had a ton of steering in and out of the corner, I could get hard on the gas coming out of the corner and the rear end didn't step out on me once. Point is every car as a weak point, the Pro 4's just happens to be the diff.
