Cheaper than dirt 318 build

So I need to pretty up the motor (obviously) so there's about 50$, rebuild kit 200$ is step one, engine will be apart so what needs done Internally should be done then at that time. What I'm getting is I should get a mild cam, and a good 2 barrel? Would a 4 barrel and intake make a big difference? (Big enough to spend the money on it?) And that's all before even getting into the electrical bits. Spark plugs, electronic ignition stuffs, coils/wires and what not. Would pistons be worth the consideration? Would my 2 and a half inch exaust I currently got work if I make the headers on the 318 hook up?