If it still has the original firing pin it is most likely made of titanium. The lighter titanium pin does not hit as hard as a steel pin. Also be aware that Springfield uses an odd size for their firing pins.
I run a GI plug & guide rod, prefer it over the full length guide rods. The GI set up makes disassembly easier as well. Sorry but I'm not educated on what the drilled rod refers to either.
I think the best thing you could do for yourself would be to find an experianced 3gun shooter and ask if he would let you take a look at his gear.
You sure don't want to show up for your first match and realize you don't have what you need.
+1 on it being addicting