He can leave all that stuff stock unless he plans on going for much bigger mods, such as FI. Many manufacturers post their recommendations for fuel injectors when you purchase their products. The TB isn't really needed unless you are adding some bigger mods like cams, heads, etc. Same goes for the fuel pump.
Of course, there isn't anything that says he can't change any of that stuff, but it just seems like he would be wasting his money if he did.