What is the Torque and Speed on that servo?
Here is the order i would upgrade a standard xxx-nt knowing you have a good engine you just bought
1. Rock Concepts Rear Aluminum Pivot block (get this one, its for teh AD2, the other ones you see have 2 degrees of rear toe-in, i think the AD2 calls for like 3 or 4 degrees? Aaron can clear that up
2. Get your self the good AD2 shocks and a spring assortment
3. Good Steering Servo. like 90+oz. of torque, .10 or below for speed
4. Good built tranny, Acer ceramic dif balls are nice, My dif is still butter smooth after 1.5 gallons of fuel.