What B4 do you have ? I thought all but the RTR come with Ti turnbuckles now ?
if not, then the Ti turnbuckles and maybe the blue alloy front hinge pin brace if you dont have one.
Ti hingepins ? nah, softer than the steel ones. Ti anything else ? nah. There are some mods that people do, like adding lead to the car. But a bog standard car can win nationals without any fancy stuff.
Have a look for a setup for southport though, you might need to get some springs and shock oil to get things going their best - don't under estimate the power of a good setup!
As for the charger - hmmmm, I've had the same charger for years but I'd have a look round for a decent cheap peak charger that will work with NiMh cells, you want to look after the cells and charge then with a decent charger.